1. A coupler, comprising:

a tubular conduit having a length disposed between a conduit first end and a conduit second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said conduit first end and said conduit second end; and

a tubular guide coupled to said conduit first end, said tubular guide widening between said conduit first end and a tubular guide terminal end, said tubular guide including:

a first tubular guide first region proximate said conduit first end; a first tubular guide second region disposed adjacent said first tubular region and extending toward said tubular guide terminal end;

said first tubular guide first region having a first radius of curvature along the longitudinal axis of said tubular guide;

said first tubular guide second region having a second radius of curvature along the longitudinal axis of said tubular guide, said second radius of curvature less than said first radius of curvature.

2. The coupler of claim 1, wherein said first tubular guide first region has a first radius of curvature of about 0.450 inches (11.43 millimeters) to about 0.700 inches (17.78 millimeters).

3. The coupler of claim 2, wherein said first radius of curvature is selected from the group consisting of: about 0.460 inches to about 0.500 inches, about 0.475 inches to about 0.525 inches, about 0.500 inches to about 0.550 inches, about 0.525 inches to about 0.575 inches, about 0.550 inches to about 0.600 inches, about 0.575 inches to about 0.625 inches, about 0.600 inches to about 0.650 inches, about 0.625 inches to about 0.675 inches, about 0.650 inches to about 0.690 inches, and combinations thereof. 4. The coupler of claim 2, wherein said first tubular guide second region has a second radius of curvature of about 0.150 inches (3.81 millimeters) to about 0.450 inches (11.43 millimeters).

5. The coupler of claim 4, wherein said second radius of curvature is selected from the group consisting of: about 0.160 inches to about 0.200 inches, about 0.175 inches to about 0.225 inches, about 0.200 inches to about 0.250 inches, about 0.225 inches to about 0.275 inches, about 0.250 inches to about 0.300 inches, about 0.275 inches to about 0.325 inches, about 0.300 inches to about 0.350 inches, about 0.325 inches to about 0.375 inches, about 0.350 inches to about 0.400 inches, about 0.375 inches to about 0.425 inches, about 0.400 inches to about 0.440 inches, and combinations thereof.

6. The coupler of claim 1, wherein a ratio of a cross-section area of said first tubular guide at said tubular guide terminal end orthogonal to a longitudinal axis of said tubular conduit to a cross-section area of said first tubular guide at said conduit first end orthogonal to said longitudinal axis of said tubular conduit comprises about 1:0.75 to about 1:0.95.

7. The coupler of claim 6, wherein said ratio is selected from the group consisting of: about 1 :0.76 to about 1 :0.77, about 1 :0.765 to about 1 :0.775, about 1 :0.77 to about 1 :0.78, about 1 :0.775 to about 1:0.785, about 1:0.78 to about 1:0.79, about 1:0.785 to about 1:0.795, about 1:0.79 to about 1:0.80, about 1:0.795 to about 1:0.805, about 1:0.80 to about 1:0.81, about 1:0.805 to about 1:0.815, about 1:0.81 to about 1:0.82, about 1:0.815 to about 1:0.825, about 1:0.82 to about 1:0.83, about 1:0.825 to about 1:0.835, about 1:0.83 to about 1:0.84, about 1:0.835 to about 1:0.845, about 1:0.84 to about 1:0.85, about 1:0.845 to about 1:0.855, about 1:0.85 to about 1:0.86, about 1:0.855 to about 1:0.865, about 1:0.86 to about 1:0.87, about 1:0.865 to about 1:0.875, about 1:0.87 to about 1:0.88, about 1:0.875 to about 1:0.885, about 1:0.88 to about 1:0.89, about 1:0.885 to about 1:0.895, about 1:0.89 to about 1:0.90, about 1:0.895 to about 1:0.905, about 1:0.90 to about 1:0.91, about 1:0.905 to about 1:0.915, about 1:0.91 to about 1:0.92, about 1:0.915 to about 1:0.925, about 1:0.92 to about 1:0.93, about 1:0.925 to about 1:0.935, about 1:0.93 to about 1:0.94, and combinations thereof. 8. The coupler of claim 1, further comprising a first external annular member circumferentially disposed on said external surface, said first external annular member overlaying a first internal annular groove circumferentially disposed on said internal surface of said tubular conduit.

9. The coupler of claim 8, further comprising an external annular groove circumferentially disposed on said external surface of said tubular conduit, said external annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

10. The coupler of claim 9, further comprising a second external annular member circumferentially disposed on said external surface of said tubular conduit overlaying a second internal annular groove circumferentially disposed on said internal surface of said tubular conduit.

11. The coupler of claim 10, wherein said first external annular member overlaying said first annular groove and said second external annular member overlaying said second internal annular groove disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove, said external annular groove overlaying said internal annular member disposed proximate said second end.

12. The coupler of claim 11, wherein said internal surface of said tubular conduit tapers from said conduit first end approaching said first internal annular groove. 13. The coupler of claim 12, wherein said internal surface of said tubular conduit tapers about 0.01 inches (0.25 millimeters) to about 0.04 inches (1.02 millimeters) between said first end and said first internal annular groove.

14. The coupler of claim 13, wherein said internal surface of said tubular conduit tapers between said first end of said tubular conduit and said first internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.020 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, about 0.028 inches to about 0.030 inches, about 0.029 inches to about 0.031 inches, about 0.030 inches to about 0.032 inches, about 0.031 inches to about 0.033 inches, about 0.032 inches to about 0.034 inches, about 0.033 inches to about 0.035 inches, about 0.034 inches to about 0.036 inches, about 0.035 inches to about 0.037 inches, about 0.036 inches to about 0.038 inches, about 0.037 inches to about 0.039 inches, and combinations thereof.

15. The coupler of claim 12, wherein said internal surface of said tubular conduit tapers approaching said internal annular member. 16. The coupler of claim 15, wherein said internal surface of said tubular conduit tapers about 0.0 inch to about 0.01 inch (0.254 inches) between said conduit second end and said internal annular member.

17. The coupler of claim 16, wherein said internal surface of said tubular conduit tapers between said second end and said internal annular member in an amount selected from the group consisting of: about 0.001 inches to about 0.003 inches, about 0.002 inches to about 0.004 inches, about 0.003 inches to about 0.005 inches, about 0.004 inches to about 0.006 inches, about 0.005 inches to about 0.007 inches, about 0.006 inches to about 0.008 inches, about 0.007 inches to about 0.009 inches, and combinations thereof.

18. The coupler of claim 1, wherein said thickness of said conduit wall comprises about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

19. The coupler of claim 18, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

20. The coupler of claim 11, wherein each of said first and second external annular members include a crown disposed between a pair of sides which taper towards said external surface, wherein said crown and said internal annular groove have substantially equal width, wherein said crown has a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove.

21. The coupler of claim 20, wherein said first internal annular groove, said second internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

22. The coupler of claim 21, wherein said depth of said first internal annular groove, said second internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches, and combinations thereof.

23. The coupler of claim 1, wherein said length of said tubular conduit is between about 6.5 (165.1 millimeters) inches to about 8.5 inches (215.9 millimeters).

24. The coupler of claim 23, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

25. The coupler of claim 23, wherein said tubular conduit is produced from a material selected from the group consisting of: metal, copper, concrete, polyvinyl chloride, acrylonitrile butadiene styrene, polyethylene, and combinations thereof. 26. The coupler of claim 23, wherein said tubular conduit has a generally cylindrical internal surface.

27. The coupler of 26, wherein said cylindrical internal surface has a diameter of about 0.5 inches (12.7 millimeters) to about 4.5 inches (114.3 millimeters).

28. The coupler of claim 27, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1.0 inch to about 1.5 inches, about 1.25 inches to about 1.75 inches, about 1.5 inches to about 2.0 inches, about 1.75 inches to about 2.25 inches, about 2.0 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3.0 inches, about 2.75 inches to about 3.25 inches, about 3.0 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4.0 inches, about 3.75 inches to about 4.25 inches, and combinations thereof.

29. The coupler of claim 21, further comprising a seal element disposed in said first internal annular groove, wherein a portion of said seal element extending outward of said internal surface into said interior passage.

30. The coupler of claim 29, wherein said seal element comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, and combinations thereof.

31. The coupler of claim 29, further comprising an annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

32. A coupler, comprising:

a tubular conduit having a length disposed between a conduit first end and a conduit second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said conduit first end and said conduit second end;

a first tubular guide coupled to said conduit first end, said first tubular guide widening between said conduit first end and a first tubular guide terminal end, said first tubular guide including:

a first tubular guide first region proximate said conduit first end; a first tubular guide second region disposed adjacent said first tubular guide region and extending toward said first tubular guide terminal end;

said first tubular guide first region having a first radius of curvature along a longitudinal axis of said first tubular guide;

said tubular guide second region having a second radius of curvature along said longitudinal axis of said first tubular guide, said second radius of curvature less than said first radius of curvature;

a second tubular guide coupled to said conduit second end, said second tubular guide widening between said conduit second end and a second tubular guide terminal end, said second tubular guide including:

a second tubular guide first region proximate said conduit second end;

a second tubular guide second region disposed adjacent said second tubular guide second region and extending toward said second tubular guide terminal end;

said second tubular guide first region having a third radius of curvature along the longitudinal axis of said second tubular guide;

said second tubular guide second region having a fourth radius of curvature along the longitudinal axis of said second tubular guide, said fourth radius of curvature less than said third radius of curvature.

33. The coupler of claim 32, wherein said first tubular guide first region has a first radius of curvature of about 0.450 inches (11.43 millimeters) to about 0.700 inches (17.78 millimeters).

34. The coupler of claim 33, wherein said first radius of curvature is selected from the group consisting of: about 0.460 inches to about 0.500 inches, about 0.475 inches to about 0.525 inches, about 0.500 inches to about 0.550 inches, about 0.525 inches to about 0.575 inches, about 0.550 inches to about 0.600 inches, about 0.575 inches to about 0.625 inches, about 0.600 inches to about 0.650 inches, about 0.625 inches to about 0.675 inches, about 0.650 inches to about 0.690 inches, and combinations thereof.

35. The coupler of claim 34, wherein said first tubular guide second region has a second radius of curvature of about 0.150 inches (3.81 millimeters) to about 0.450 inches (11.43 millimeters).

36. The coupler of claim 35, wherein said second radius of curvature is selected from the group consisting of: about 0.160 inches to about 0.200 inches, about 0.175 inches to about 0.225 inches, about 0.200 inches to about 0.250 inches, about 0.225 inches to about 0.275 inches, about 0.250 inches to about 0.300 inches, about 0.275 inches to about 0.325 inches, about 0.300 inches to about 0.350 inches, about 0.325 inches to about 0.375 inches, about 0.350 inches to about 0.400 inches, about 0.375 inches to about 0.425 inches, about 0.400 inches to about 0.440 inches, and combinations thereof.

37. The coupler of claim 36, wherein said second tubular guide first region has a third radius of curvature of about 0.450 inches (11.43 millimeters) to about 0.700 inches (17.78 millimeters). 38. The coupler of claim 37, wherein said third radius of curvature is selected from the group consisting of: about 0.460 inches to about 0.500 inches, about 0.475 inches to about 0.525 inches, about 0.500 inches to about 0.550 inches, about 0.525 inches to about 0.575 inches, about 0.550 inches to about 0.600 inches, about 0.575 inches to about 0.625 inches, about 0.600 inches to about 0.650 inches, about 0.625 inches to about 0.675 inches, about 0.650 inches to about 0.690 inches, and combinations thereof.

39. The coupler of claim 38, wherein said second tubular guide second region has a fourth radius of curvature of about 0.150 inches (3.81 millimeters) to about 0.450 inches (11.43 millimeters).

40. The coupler of claim 39, wherein said fourth radius of curvature is selected from the group consisting of: about 0.160 inches to about 0.200 inches, about 0.175 inches to about 0.225 inches, about 0.200 inches to about 0.250 inches, about 0.225 inches to about 0.275 inches, about 0.250 inches to about 0.300 inches, about 0.275 inches to about 0.325 inches, about 0.300 inches to about 0.350 inches, about 0.325 inches to about 0.375 inches, about 0.350 inches to about 0.400 inches, about 0.375 inches to about 0.425 inches, about 0.400 inches to about 0.440 inches, and combinations thereof. 41. The coupler of claim 40, wherein a ratio of a cross-section area of said first tubular guide at said tubular guide terminal end orthogonal to a longitudinal axis of said tubular conduit to a cross-section area of said tubular guide at said conduit first end orthogonal to said longitudinal axis of said tubular conduit comprises a first ratio of about 1 :0.75 to about 1 :0.95.

42. The coupler of claim 41, wherein said first ratio is selected from the group consisting of: about 1:0.76 to about 1:0.77, about 1:0.765 to about 1:0.775, about 1:0.77 to about 1:0.78, about

1:0.775 to about 1:0.785, about 1:0.78 to about 1:0.79, about 1:0.785 to about 1:0.795, about 1:0.79 to about 1:0.80, about 1:0.795 to about 1:0.805, about 1:0.80 to about 1:0.81, about 1:0.805 to about 1:0.815, about 1:0.81 to about 1:0.82, about 1:0.815 to about 1:0.825, about 1:0.82 to about 1:0.83, about 1:0.825 to about 1:0.835, about 1:0.83 to about 1:0.84, about 1:0.835 to about 1:0.845, about 1:0.84 to about 1:0.85, about 1:0.845 to about 1:0.855, about 1:0.85 to about 1:0.86, about 1:0.855 to about 1:0.865, about 1:0.86 to about 1:0.87, about 1:0.865 to about 1:0.875, about 1:0.87 to about 1:0.88, about 1:0.875 to about 1:0.885, about 1:0.88 to about 1:0.89, about 1:0.885 to about 1:0.895, about 1:0.89 to about 1:0.90, about 1:0.895 to about 1:0.905, about 1:0.90 to about 1:0.91, about 1:0.905 to about 1:0.915, about 1:0.91 to about 1:0.92, about 1:0.915 to about 1:0.925, about 1:0.92 to about 1:0.93, about 1:0.925 to about 1:0.935, about 1:0.93 to about 1:0.94, and combinations thereof.

43. The coupler of claim 42, wherein a ratio of a cross-section area of said second tubular guide at said second tubular guide terminal end orthogonal to a longitudinal axis of said tubular conduit to a cross-section area of said second tubular guide at said conduit first end orthogonal to said longitudinal axis of said tubular conduit comprises a second ratio of about 1 :0.75 to about 1:0.95.

44. The coupler of claim 43, wherein said second ratio is selected from the group consisting of: about 1:0.76 to about 1:0.77, about 1:0.765 to about 1:0.775, about 1:0.77 to about 1:0.78, about 1:0.775 to about 1:0.785, about 1:0.78 to about 1:0.79, about 1:0.785 to about 1:0.795, about 1:0.79 to about 1:0.80, about 1:0.795 to about 1:0.805, about 1:0.80 to about 1:0.81, about 1:0.805 to about 1:0.815, about 1:0.81 to about 1:0.82, about 1:0.815 to about 1:0.825, about 1:0.82 to about 1:0.83, about 1:0.825 to about 1:0.835, about 1:0.83 to about 1:0.84, about 1:0.835 to about 1 :0.845, about 1 :0.84 to about 1 :0.85, about 1 :0.845 to about 1 :0.855, about 1 :0.85 to about 1 :0.86, about 1 :0.855 to about 1 :0.865, about 1 :0.86 to about 1 :0.87, about 1 :0.865 to about 1 :0.875, about 1 :0.87 to about 1 :0.88, about 1 :0.875 to about 1 :0.885, about 1 :0.88 to about 1 :0.89, about 1 :0.885 to about 1 :0.895, about 1 :0.89 to about 1 :0.90, about 1 :0.895 to about 1 :0.905, about 1 :0.90 to about 1 :0.91, about 1 :0.905 to about 1 :0.915, about 1 :0.91 to about 1 :0.92, about 1 :0.915 to about 1 :0.925, about 1 :0.92 to about 1 :0.93, about 1 :0.925 to about 1 :0.935, about 1 :0.93 to about 1 :0.94, and combinations thereof.

45. The coupler of claim 44, further comprising an external annular groove circumferentially disposed on said external surface of said tubular conduit, said annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

46. The coupler of claim 45, further comprising:

a plurality of external annular members circumferentially disposed on said external surface overlaying a corresponding plurality of internal annular grooves circumferentially disposed on said internal surface of said tubular conduit, said plurality of external annular members including a first external annular member, a second external annular member, a third external annular member, and a fourth external annular member each correspondingly overlaying one of said plurality of internal annular grooves, and wherein said plurality of internal annular grooves includes a first internal annular groove, a second internal annular grooves, a third internal annular groove, and fourth internal annular groove;

said first and second external annular members correspondingly overlaying said first and second annular grooves disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove; and

said third and fourth external annular members overlaying said third and fourth annular grooves disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said second end, said third external annular member overlaying said third internal annular groove disposed a lesser distance from said second end than said fourth external annular member overlaying said fourth internal annular groove.

47. The coupler of claim 46, wherein said external annular groove overlaying an internal annular member medially disposed on said tubular conduit.

48. The coupler of claim 47, wherein said internal surface of said tubular conduit tapers approaching said first external annular member.

49. The coupler of claim 48, wherein said internal surface of said tubular conduit tapers about 0.01 inches (0.254 millimeters) to about 0.04 inches (0.762 millimeters) between said first end and said first internal annular groove.

50. The coupler of claim 49, wherein said internal surface of said tubular conduit tapers between said first end and said first internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.020 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, about 0.028 inches to about 0.030 inches, about 0.029 inches to about 0.031 inches, about 0.030 inches to about 0.032 inches, about 0.031 inches to about 0.033 inches, about 0.032 inches to about 0.034 inches, about 0.033 inches to about 0.035 inches, about 0.034 inches to about 0.036 inches, about 0.035 inches to about 0.037 inches, about 0.036 inches to about 0.038 inches, about 0.037 inches to about 0.039 inches, and combinations thereof. 51. The coupler of claim 50, wherein said internal surface of said tubular conduit tapers approaching said third external annular member.

52. The coupler of claim 51, wherein said internal surface of said tubular conduit tapers about 0.01 inches (0.254 millimeters) to about 0.04 inches (0.762 millimeters) between said second end and said third internal annular groove. 53. The coupler of claim 52, wherein said internal surface of said tubular conduit tapers between said second end and said third internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.020 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, about 0.028 inches to about 0.030 inches, about 0.029 inches to about 0.031 inches, about 0.030 inches to about 0.032 inches, about 0.031 inches to about 0.033 inches, about 0.032 inches to about 0.034 inches, about 0.033 inches to about 0.035 inches, about 0.034 inches to about 0.036 inches, about 0.035 inches to about 0.037 inches, about 0.036 inches to about 0.038 inches, about 0.037 inches to about 0.039 inches, and combinations thereof.

54. The coupler of claim 53, wherein said thickness of said conduit wall is about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

55. The coupler of claim 54, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

56. The coupler of claim 55, wherein said first external annular member, said second external annular member, said third external annular member, and said fourth external annular member each include a crown disposed between a pair of sides which taper towards said external surface of said tubular conduit, each said crown and each said internal annular groove having substantially equal width, each said crown having a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove. 57. The coupler of claim 56, wherein said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

58. The coupler of claim 57, wherein said depth of said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches, and combinations thereof.

59. The coupler of claim 58, wherein said length of said tubular conduit about 6.5 inches (165.1 millimeters) to about 8.5 inches (215.9 millimeters). 60. The coupler of claim 59, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

61. The coupler of claim 60, wherein said material comprising said tubular conduit selected from the group consisting of: metal, copper, concrete, polyvinyl chloride, acrylonitrile butadiene styrene, polyethylene, and combinations thereof.

62. The coupler of claim 61, wherein said tubular conduit has a generally cylindrical internal surface.

63. The coupler of claim 62, wherein said cylindrical internal surface has a diameter of about 0.5 inches (12.7 millimeters) to about 4.5 inches (114.3 millimeters).

64. The coupler of claim 63, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1.0 inch to about 1.5 inches, about 1.25 inches to about 1.75 inches, about 1.5 inches to about 2.0 inches, about 1.75 inches to about 2.25 inches, about 2.0 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3.0 inches, about 2.75 inches to about 3.25 inches, about 3.0 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4.0 inches, about 3.75 inches to about 4.25 inches, and combinations thereof.

65. The coupler of claim 64, further comprising a first seal element disposed in said first internal annular groove, wherein a portion of said first seal element extending outward of said internal surface into said interior passage.

66. The coupler of claim 65, further comprising a second seal element disposed in said third internal annular groove, wherein a portion of said second seal element extending outward of said internal surface into said interior passage.

67. The coupler of claim 66, wherein said seal element comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, or combinations thereof.

68. The coupler of claim 67, further comprising a first annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

69. The coupler of claim 68, further comprising a second annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said fourth internal annular groove.

70. A method of using a coupler, comprising:

positioning a coupler in spatial relation to a pipe first end, said coupler including:

a tubular conduit having a length disposed between a conduit first end and a conduit second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said conduit first end and said conduit second end; and

a tubular guide coupled to said conduit first end, said tubular guide widening between said conduit first end and a tubular guide terminal end, said tubular guide including:

a first tubular guide first region proximate said conduit first end;

a first tubular guide second region disposed adjacent said first tubular region and extending toward said tubular guide terminal end;

said first tubular guide first region having a first radius of curvature along the longitudinal axis of said tubular guide; said first tubular guide second region having a second radius of curvature along the longitudinal axis of said tubular guide, said second radius of curvature less than said first radius of curvature;

engaging a pipe first end to said tubular guide proximate said tubular guide terminal end, said pipe first end disposed in angled relation to a longitudinal axis of said tubular guide;

forcibly urging said pipe first end along said tubular guide; and

guiding said pipe first end into said interior passage of said tubular conduit.

71. The method of claim 70, wherein said first tubular guide first region has a first radius of curvature of about 0.450 inches (11.43 millimeters) to about 0.700 inches (17.78 millimeters). 72. The method of claim 71, wherein said first radius of curvature is selected from the group consisting of: about 0.460 inches to about 0.500 inches, about 0.475 inches to about 0.525 inches, about 0.500 inches to about 0.550 inches, about 0.525 inches to about 0.575 inches, about 0.550 inches to about 0.600 inches, about 0.575 inches to about 0.625 inches, about 0.600 inches to about 0.650 inches, about 0.625 inches to about 0.675 inches, about 0.650 inches to about 0.690 inches, and combinations thereof.

73. The method of claim 72, wherein said first tubular guide second region has a second radius of curvature of about 0.150 inches (3.81 millimeters) to about 0.450 inches (11.43 millimeters).

74. The method of claim 73, wherein said second radius of curvature is selected from the group consisting of: about 0.160 inches to about 0.200 inches, about 0.175 inches to about 0.225 inches, about 0.200 inches to about 0.250 inches, about 0.225 inches to about 0.275 inches, about 0.250 inches to about 0.300 inches, about 0.275 inches to about 0.325 inches, about 0.300 inches to about 0.350 inches, about 0.325 inches to about 0.375 inches, about 0.350 inches to about 0.400 inches, about 0.375 inches to about 0.425 inches, about 0.400 inches to about 0.440 inches, and combinations thereof. 75. The method of claim 74, wherein a ratio of a cross-section area of said first tubular guide at said tubular guide terminal end orthogonal to a longitudinal axis of said tubular conduit to a cross-section area of said first tubular guide at said conduit first end orthogonal to said longitudinal axis of said tubular conduit comprises about 1 :0.75 to about 1 :0.95.

76. The method of claim 75, wherein said ratio is selected from the group consisting of: about 1 :0.76 to about 1 :0.77, about 1 :0.765 to about 1 :0.775, about 1 :0.77 to about 1 :0.78, about 1 :0.775 to about 1 :0.785, about 1 :0.78 to about 1 :0.79, about 1 :0.785 to about 1 :0.795, about 1 :0.79 to about 1:0.80, about 1:0.795 to about 1:0.805, about 1:0.80 to about 1:0.81, about 1:0.805 to about 1:0.815, about 1:0.81 to about 1:0.82, about 1:0.815 to about 1:0.825, about 1:0.82 to about 1:0.83, about 1:0.825 to about 1:0.835, about 1:0.83 to about 1:0.84, about 1:0.835 to about 1:0.845, about 1:0.84 to about 1:0.85, about 1:0.845 to about 1:0.855, about 1:0.85 to about 1:0.86, about 1:0.855 to about 1:0.865, about 1:0.86 to about 1:0.87, about 1:0.865 to about 1:0.875, about 1:0.87 to about 1:0.88, about 1:0.875 to about 1:0.885, about 1:0.88 to about 1:0.89, about 1:0.885 to about 1:0.895, about 1:0.89 to about 1:0.90, about 1:0.895 to about 1:0.905, about 1:0.90 to about 1:0.91, about 1:0.905 to about 1:0.915, about 1:0.91 to about 1:0.92, about 1:0.915 to about 1:0.925, about 1:0.92 to about 1:0.93, about 1:0.925 to about 1:0.935, about 1:0.93 to about 1:0.94, and combinations thereof.

77. The method of claim 76, wherein said coupler further comprises:

a first external annular member circumferentially disposed on said external surface, said first external annular member overlaying a first internal annular groove circumferentially disposed on said internal surface of said tubular conduit;

a second external annular member circumferentially disposed on said external surface of said tubular conduit overlaying a second internal annular groove circumferentially disposed on said internal surface of said tubular conduit;

said first external annular member overlaying said first annular groove and said second external annular member overlaying said second internal annular groove disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove; and

a seal element disposed in said first internal annular groove, wherein a portion of said seal element extending outward of said internal surface into said interior passage further comprises sealably engaging said pipe to said seal element.

78. The method of claim 77, further comprising sealably engaging said pipe to said seal element.

79. The method of claim 78, wherein said coupler further comprises an annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

80. The method of claim 79, further comprising forcibly urging said pipe into said interior passage and flexing said resiliently flexible tabs of said annular retaining member.

81. A coupler, comprising:

a tubular conduit having a length disposed between a first end and a second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends; and

a first external annular member circumferentially disposed on said external surface, said first external annular member overlaying a first internal annular groove circumferentially disposed on said internal surface of said tubular conduit. 82. The coupler of claim 81, further comprising an external annular groove circumferentially disposed on said external surface of said tubular conduit, said annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

83. The coupler of claim 82, further comprising a second external annular member circumferentially disposed on said external surface of said tubular conduit overlaying a second internal annular groove circumferentially disposed on said internal surface of said tubular conduit.

84. The coupler of claim 83, wherein said first external annular member overlaying said first annular groove and said second external annular member overlaying said second internal annular groove disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove, said external annular groove overlaying said internal annular member disposed proximate said second end. 85. The coupler of claim 84, wherein said internal surface tapers approaching said first internal annular groove.

86. The coupler of claim 85, wherein said internal surface tapers about 0.01 inches (0.254 millimeters) to about 0.03 inches (0.762 millimeters) between said first end and said first internal annular groove. 87. The coupler of claim 86, wherein said internal surface tapers between said first end and said first internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.24 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof.

88. The coupler of claim 87, wherein said internal surface tapers approaching said internal annular member.

89. The coupler of claim 88, wherein said internal surface tapers about 0.0 inch to about 0.01 inch (0.254 inches) between said second end and said internal annular member.

90. The coupler of claim 89, wherein said internal surface tapering between said second end and said internal annular member in an amount selected from the group consisting of: about 0.001 inches to about 0.003 inches, about 0.002 inches to about 0.004 inches, about 0.003 inches to about 0.005 inches, about 0.004 inches to about 0.006 inches, about 0.005 inches to about 0.007 inches, about 0.006 inches to about 0.008 inches, about 0.007 inches to about 0.009 inches, and combinations thereof.

91. The coupler of claim 90, wherein said conduit wall has a thickness of about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

92. The coupler of claim 91, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

93. The coupler of claim 92, wherein each of said first and second external annular members include a crown disposed between a pair of sides which taper towards said external surface, wherein said crown and said internal annular groove have substantially equal width, wherein said crown has a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove.

94. The coupler of claim 93, wherein said first internal annular groove, said second internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

95. The coupler of claim 94, wherein said depth of said first internal annular groove, said second internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches and combinations thereof.

96. The coupler of claim 95, wherein said length of said tubular conduit is between about 6.5 (165.1 millimeters) inches to about 8.5 inches (215.9 millimeters). 97. The coupler of claim 96, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

98. The coupler of claim 97, wherein said tubular conduit is produced from a material selected from the group consisting of: polyvinyl chloride, copper, concrete, acrylonitrile butadiene styrene, polyethylene, and combinations thereof.

99. The coupler of claim 98, wherein said tubular conduit has a generally cylindrical internal surface.

100. The coupler of claim 99, wherein said cylindrical internal surface has a diameter of about 0.5 inch (12.7 millimeters) to about 4.5 inches (114.3 millimeters).

101. The coupler of claim 100, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1 inch to about 1.5 inches, about 1.25 inches to about 1.75 inches, about 1.5 inches to about 2 inches, about 1.75 inches to about 2.25 inches, about 2 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3 inches, about 2.75 inches to about 3.25 inches, about 3 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4 inches, about 3.75 inches to about 4.25 inches, and combinations thereof.

102. The coupler of claim 101, further comprising a seal element disposed in said first internal annular groove, wherein a portion of said seal element extending outward of said internal surface into said interior passage.

103. The coupler of claim 102, wherein said seal element comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, or combinations thereof. 104. The coupler of claim 103, further comprising an annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove. 105. A coupler, comprising:

a tubular conduit having a length disposed between a first end and a second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends; and

an external annular groove circumferentially disposed on said external surface of said tubular conduit, said annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

106. The coupler of claim 105, further comprising a plurality of external annular members circumferentially disposed on said external surface overlaying a corresponding plurality of internal annular grooves circumferentially disposed on said internal surface of said tubular conduit.

107. The coupler of claim 106, wherein said plurality of external annular members includes a first external annular member, a second external annular member, a third external annular member, and a fourth external annular member each correspondingly overlaying one of said plurality of internal annular grooves, and wherein said plurality of internal annular grooves includes a first internal annular groove, a second internal annular grooves, a third internal annular groove, and a fourth internal annular groove.

108. The coupler of claim 107, wherein said first and second external annular members correspondingly overlaying said first and second annular groove elements disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove.

109. The coupler of claim 108, wherein said third and fourth external annular members overlaying said third and fourth annular groove elements disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said second end, said third external annular member overlaying said third internal annular groove disposed a lesser distance from said second end than said fourth external annular member overlaying said fourth internal annular groove.

110. The coupler of claim 109, wherein said external annular groove overlaying an internal annular member medially disposed on said tubular conduit.

111. The coupler of claim 110, wherein said internal surface tapers approaching said first external annular member.

112. The coupler of claim 111, wherein said internal surface tapers about 0.01 inches (0.254 millimeters) to about 0.03 inches (0.762 millimeters) between said first end and said first internal annular groove.

113. The coupler of claim 112, wherein said internal surface tapers between said first end and said first internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof. 114. The coupler of claim 113, wherein said internal surface tapers approaching said third external annular member.

115. The coupler of claim 114, wherein said internal surface tapers about 0.01 (0.254 inches) inches to about 0.03 inches (0.762 millimeters) between said second end and said third internal annular groove. 116. The coupler of claim 115, wherein said internal surface tapers between said second end and said third internal annular groove in an amount selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof. 117. The coupler of claim 116, wherein said thickness of said conduit wall is about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

118. The coupler of claim 117, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

119. The coupler of claim 118, wherein said first external annular member, a second external annular member, a third external annular member, and a fourth external annular member each include a crown disposed between a pair of sides which taper towards said external surface, each said crown and each said internal annular groove having substantially equal width, each said crown having a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove.

120. The coupler of claim 119, wherein said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

121. The coupler of claim 120, wherein said depth of said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches and combinations thereof.

122. The coupler of claim 121, wherein said length of said tubular conduit between about 6.5 (165.1 millimeters) inches to about 8.5 inches (215.9 millimeters).

123. The coupler of claim 122, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

124. The coupler of claim 123, wherein said material comprising said tubular conduit selected from the group consisting of: polyvinyl chloride, copper, concrete, acrylonitrile butadiene styrene, polyethylene, and combinations thereof.

125. The coupler of claim 124, wherein said tubular conduit has a generally cylindrical internal surface.

126. The coupler of claim 125, wherein said cylindrical internal surface has a diameter of about 0.5 inch (12.7 millimeters) to about 4.5 inches (114.3 millimeters). 127. The coupler of claim 126, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1 inch to about 1.5 inches, about 1.25 inches to about 1.75 inches, about 1.5 inches to about 2 inches, about 1.75inches to about 2.25 inches, about 2 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3 inches, about 2.75 inches to about 3.25 inches, about 3 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4 inches, about 3.75 inches to about 4.25 inches, and combinations thereof.

128. The coupler of claim 127, further comprising a first seal element disposed in said first internal annular groove, wherein a portion of said first seal element extending outward of said internal surface into said interior passage. 129. The coupler of claim 128, further comprising a second seal element disposed in said third internal annular groove, wherein a portion of said second seal element extending outward of said internal surface into said interior passage.

130. The coupler of claim 129, wherein said seal element comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, or combinations thereof.

131. The coupler of claim 130, further comprising a first annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

132. The coupler of claim 131, further comprising a second annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said fourth internal annular groove.

133. A coupler, consisting of:

a tubular conduit having a length disposed between a first end and a second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends;

a first external annular member circumferentially disposed on said external surface, said annular member overlaying a first internal annular groove circumferentially disposed on said internal surface of said tubular conduit;

a second external annular member circumferentially disposed on said external surface of said tubular conduit overlaying a second internal annular groove circumferentially disposed on said internal surface of said tubular conduit, wherein said first external annular member overlaying said first annular groove and said second external annular member overlaying said second internal annular groove disposed in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove, said external annular groove overlaying said internal annular member disposed proximate said second end; and

an external annular groove circumferentially disposed on said external surface of said tubular conduit, said annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit. 134. The coupler of claim 133, further consisting of a first seal element disposed in said first internal annular groove, wherein a portion of said first seal element extending outward of said internal surface into said interior passage.

135. The coupler of claim 134, further consisting of a first annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

136. A coupler, consisting of:

a tubular conduit having a length disposed between a first end and a second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends;

a first and second external annular member disposed on said external surface correspondingly overlaying a first and second annular groove disposed on said internal surface, said first external annular member overlaying said first internal annular groove disposed a lesser distance axially from said first end than said second external annular member overlaying said second internal annular groove;

a third and fourth external annular member disposed on said external surface correspondingly overlaying a third and fourth annular groove disposed on said internal surface, said first external annular member overlaying said first internal annular groove disposed a lesser distance axially from said first end than said second external annular member overlaying said second internal annular groove; and

an external annular groove circumferentially disposed on said external surface of said tubular conduit overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit, wherein said external annular groove overlaying said internal annular member medially disposed on said tubular conduit.

137. The coupler of claim 136, further consisting of a first seal element disposed in said first internal annular groove, wherein a portion of said first seal element extending outward of said internal surface into said interior passage.

138. The coupler of claim 137, further consisting of a second seal element disposed in said third internal annular groove, wherein a portion of said second seal element extending outward of said internal surface into said interior passage.

139. The coupler of claim 138, further consisting of a first annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove.

140. The coupler of claim 139, further consisting of a second annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said fourth internal annular groove.

141. A method of producing a coupler, comprising:

forming a tubular conduit having a length disposed between a first end and a second end and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends; and circumferentially disposing a first external annular member on said external surface, said first external annular member overlaying a first internal annular groove circumferentially disposed on said internal surface of said tubular conduit.

142. The method of claim 141, further comprising circumferentially disposing an external annular groove on said external surface of said tubular conduit, said external annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

143. The method of claim 142, further comprising circumferentially disposing a second external annular member on said external surface of said tubular conduit overlaying a second internal annular groove circumferentially disposed on said internal surface of said tubular conduit.

144. The method of claim 143, further comprising disposing said first external annular member overlaying said first annular groove and said second external annular member overlaying said second internal annular groove in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove, said external annular groove overlaying said internal annular member disposed proximate said second end. 145. The method of claim 144, further comprising circumferentially tapering said internal surface approaching said first internal annular groove.

146. The method of claim 145, wherein said internal surface tapering about 0.01 inches (0.254 millimeters) to about 0.03 inches (0.762 millimeters) between said first end and said first internal annular groove. 147. The method of claim 146, wherein said internal surface tapering between said first end and said first internal annular groove selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof.

148. The method of claim 147, further comprising circumferentially tapering said internal surface approaching said internal annular member.

149. The method of claim 148, wherein said internal surface circumferentially tapers about 0.0 inch to about 0.01 inch (0.254 inches) between said second end and said internal annular member.

150. The method of claim 149, wherein said internal surface tapering between said second end and said internal annular member selected from the group consisting of: about 0.001 inches to about 0.003 inches, about 0.002 inches to about 0.004 inches, about 0.003 inches to about 0.005 inches, about 0.004 inches to about 0.006 inches, about 0.005 inches to about 0.007 inches, about 0.006 inches to about 0.008 inches, about 0.007 inches to about 0.009 inches, and combinations thereof.

151. The method of claim 150, wherein said thickness of said conduit wall about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

152. The method of claim 151, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

153. The method of claim 152, further comprising configuring said first and second external annular members to have a crown and each side of said first and second external annular members taper inward towards said external surface, have a width of said crown substantially equal to a width of said internal annular groove, and a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove.

154. The method of claim 153, wherein said first internal annular groove, said second internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

155. The method of claim 154, wherein said depth of said first internal annular groove, said second internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches and combinations thereof.

156. The method of claim 155, wherein said length of said tubular conduit between about 6.5 (165.1 millimeters) inches to about 8.5 inches (215.9 millimeters). 157. The method of claim 156, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

158. The method of claim 157, wherein said material comprising said tubular conduit selected from the group consisting of: polyvinyl chloride, copper, concrete, acrylonitrile butadiene styrene, polyethylene, and combinations thereof.

159. The method of claim 158, wherein said tubular conduit has a generally cylindrical internal surface.

160. The method of claim 159, wherein said cylindrical internal surface has a diameter of about 0.5 inch (12.7 millimeters) to about 4.5 inches (114.3 millimeters).

161. The method of claim 160, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1 inch to about 1.5 inches, about 1.25 inches to about 1.75 inches, about 1.5 inches to about 2 inches, about 1.75 inches to about 2.25 inches, about 2 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3 inches, about 2.75 inches to about 3.25 inches, about 3 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4 inches, about 3.75 inches to about 4.25 inches, and combinations thereof.

162. The method of claim 161, further comprising disposing a seal element in said first internal annular groove, wherein a portion of said seal element extending outward of said internal surface into said interior passage.

163. The method of claim 162, wherein said seal element comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, or combinations thereof. 164. The method of claim 163, further comprising configuring an annular retaining member having an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove. 165. A method of making a coupler, comprising:

obtaining a tubular conduit having:

a length disposed between a first end and a second end; and a conduit wall having a thickness disposed between an external surface and an internal surface, said internal surface defining an interior passage between said first and second ends; and

circumferentially disposing an external annular groove on said external surface of said tubular conduit, said annular groove overlaying an internal annular member circumferentially disposed on said internal surface of said tubular conduit.

166. The method of claim 165, further comprising circumferentially disposing a plurality of external annular members on said external surface overlaying a corresponding plurality of internal annular grooves circumferentially disposed on said internal surface of said tubular conduit.

167. The method of claim 166, wherein said plurality of external annular members includes a first, second, third, and fourth external annular member, and said plurality of internal annular grooves includes a first, second, third, and fourth internal annular element. 168. The method of claim 167, further comprising disposing said first and second external annular members overlaying said first and second annular groove elements in axial spaced apart relation on said external surface of said tubular conduit proximate said first end, said first external annular member overlaying said first internal annular groove disposed a lesser distance from said first end than said second external annular member overlaying said second internal annular groove. 169. The method of claim 168, further comprising disposing said third and fourth external annular members overlaying said third and fourth annular groove elements in axial spaced apart relation on said external surface of said tubular conduit proximate said second end, said third external annular member overlaying said third internal annular groove disposed a lesser distance from said second end than said fourth external annular member overlaying said fourth internal annular groove.

170. The method of claim 169, further comprising disposing said external annular groove overlaying an internal annular element medially on said tubular conduit.

171. The method of claim 170, further comprising circumferentially tapering said internal surface approaching said first external annular member. 172. The method of claim 171, wherein said internal surface tapers about 0.01 inches (0.254 millimeters) to about 0.03 inches (0.762 millimeters) between said first end and said first internal annular groove.

173. The method of claim 172, wherein said internal surface tapering between said first end and said first internal annular groove selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof.

174. The method of claim 173, further comprising circumferentially tapering said internal surface approaching said third external annular member.

175. The method of claim 174, wherein said internal surface tapers about 0.01 (0.254 inches) inches to about 0.03 inches (0.762 millimeters) between said second end and said third internal annular groove.

176. The method of claim 175, wherein said internal surface tapering between said second end and said third internal annular groove selected from the group consisting of: about 0.012 inches to about 0.014 inches, about 0.013 inches to about 0.015 inches, about 0.014 inches to about 0.016 inches, about 0.015 inches to about 0.017 inches, about 0.016 inches to about 0.018 inches, about 0.017 inches to about 0.019 inches, about 0.018 inches to about 0.20 inches, about 0.019 inches to about 0.021 inches, about 0.020 inches to about 0.022 inches, about 0.021 inches to about 0.023 inches, about 0.022 inches to about 0.024 inches, about 0.023 inches to about 0.025 inches, about 0.024 inches to about 0.026 inches, about 0.025 inches to about 0.027 inches, about 0.026 inches to about 0.028 inches, about 0.027 inches to about 0.029 inches, and combinations thereof.

177. The method of claim 176, wherein said thickness of said conduit wall about 0.15 inches (3.81 millimeters) to about 0.35 inches (8.89 millimeters).

178. The method of claim 177, wherein said thickness of said conduit wall is selected from the group consisting of: about 0.16 inches to about 0.2 inches, about 0.175 inches to about 0.225 inches, about 0.2 inches to about 0.25 inches, about 0.225 inches to about 0.275 inches, about 0.25 inches to about 0.3 inches, about 0.275 inches to about 0.325 inches, about 0.3 inches to about 0.34 inches, and combinations thereof.

179. The method of claim 178, wherein said first, second, third, and fourth external annular members configured to have a crown and each side of said first, second, third, and fourth external annular members taper inward towards said external surface, have a width of said crown substantially equal to a width of said corresponding first, second, third, and fourth internal annular groove, and a height of between about 1.0 times and about 2.0 times that of a depth of said internal annular groove.

180. The method of claim 179, wherein said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove each having a depth of about 0.1 inches (2.54 millimeters) to about 0.3 inches (7.62 millimeters).

181. The method of claim 180, wherein said depth of said first internal annular groove, said second internal annular groove, said third internal annular groove, said fourth internal annular groove, and said external annular groove selected from the group consisting of: about 0.12 inches to about 0.14 inches, about 0.13 inches to about 0.15 inches, about 0.14 inches to about 0.16 inches, about 0.15 inches to about 0.17 inches, about 0.16 inches to about 0.18 inches, about 0.17 inches to about 0.19 inches, about 0.18 inches to about 0.2 inches, about 0.19 inches to about 0.21 inches, about 0.2 inches to about 0.22 inches, about 0.21 inches to about 0.23 inches, about 0.22 inches to about 0.24 inches, about 0.23 inches to about 0.25 inches, about 0.24 inches to about 0.26 inches, about 0.25 inches to about 0.27 inches, about 0.26 inches to about 0.28 inches, about 0.27 inches to about 0.29 inches and combinations thereof.

182. The method of claim 181, wherein said length of said tubular conduit between about 6.5 (165.1 millimeters) inches to about 8.5 inches (215.9 millimeters).

183. The method of claim 182, wherein said length of said tubular conduit is selected from the group consisting of: about 6.6 inches to about 6.8 inches, about 6.7 inches to about 6.9 inches, about 6.8 inches to about 7.0 inches, about 6.9 inches to about 7.1 inches, about 7.0 inches to about 7.2 inches, about 7.1 inches to about 7.3 inches, about 7.2 inches to about 7.4 inches, about 7.3 inches to about 7.5 inches, about 7.4 inches to about 7.6 inches, about 7.5 inches to about 7.7 inches, about 7.6 inches to about 7.8 inches, about 7.7 inches to about 7.9 inches, about 7.8 inches to about 8.0 inches, about 7.9 inches to about 8.1 inches, about 8.0 inches to about 8.2 inches, about 8.1 inches to about 8.3 inches, about 8.2 inches to about 8.4 inches, and combinations thereof.

184. The method of claim 183, wherein said material comprising said tubular conduit selected from the group consisting of: polyvinyl chloride, copper, concrete, acrylonitrile butadiene styrene, polyethylene, and combinations thereof. 185. The method of claim 184, wherein said tubular conduit has a generally cylindrical internal surface.

186. The method of claim 185, wherein said cylindrical internal surface has a diameter of about 0.5 inch (12.7 millimeters) to about 4.5 inches (114.3 millimeters).

187. The method of claim 186, wherein said diameter is selected from the group consisting of: about 0.75 inch to about 1.25 inches, about 1 inch to about 1.50 inches, about 1.25 inches to about

1.75 inches, about 1.5 inches to about 2 inches, about 1.75 inches to about 2.25 inches, about 2 inches to about 2.5 inches, about 2.25 inches to about 2.75 inches, about 2.5 inches to about 3 inches, about 2.75 inches to about 3.25 inches, about 3 inches to about 3.5 inches, about 3.25 inches to about 3.75 inches, about 3.5 inches to about 4 inches, about 3.75 inches to about 4.25 inches, and combinations thereof. 188. The method of claim 187, further comprising disposing a first seal element in said first internal annular groove, wherein a portion of said first seal element extending outward of said internal surface into said interior passage.

189. The method of claim 188, further comprising disposing a second seal element in said third internal annular groove, wherein a portion of said second seal element extending outward of said internal surface into said interior passage.

190. The method of claim 189, wherein said first and second seal elements comprises a material selected from the group consisting of: ethylene propylene diene monomer, silicone, fluorocarbon, fluorosilicone, polyurethane, tetrafluoroethylene/propylene, nitrile, and neoprene, or combinations thereof. 191. The method of claim 190, further comprising configuring a first annular retaining member to have an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said second internal annular groove. 192. The method of claim 191, further comprising configuring a second annular retaining member to have an outer periphery and an inner periphery, said inner periphery having a plurality of radially extending slots in circumferentially spaced apart relation about said inner periphery defining a plurality of resiliently flexible tabs, said outer periphery disposed in said fourth internal annular groove.