P728 28 in. Plug-End Extension Spring is a spring replacement for 1-piece / tilt-up / canopy-style garage doors. Two P728 springs - one on each side of the door - can handle a 90 lbs. to 150 lbs. door, with an initial tension of 110 lbs. to 120 lbs. Four P728 springs - two on each of the door - can handle a 150 lbs. - 300 lbs. door. Either 4 c-hook's or 4 w-hook's (sold separately) are required to connect the springs to the jamb hardware.
- 2 x P728 springs support 90 lbs. to 150 lbs. garage doors
- 4 x P728 springs support 150 lbs. to 300 lbs. garage doors
- Length over coils: 28 in.
- Outside diameter: 1-5/16 in.
- Wire gauge: (0.177) no. 7
- Initial tension: 110 lbs. - 120 lbs.
- Maximum allowable stretch: 18.5 in.