SL728 28-Inch Lock-End Garage Door Extension Spring (.177" #7 Wire) SPRINGS FOR YOUR ONE-PIECE GARAGE DOOR OR TOY HAULER - SL728 springs handle a 90-150lb. door with 2 springs or a 150-300lb. door with 4 springs SIMPLE INSTALLATION - install new or replace old, rusty springs quickly and by yourself SAFETY CONTAINMENT ROD - if and when spring breaks, the coils will remain wrapped around middle rod for protection CORROSION RESISTANT - powder coated steel coils to help slow rusting process over spring life 1-YEAR WARRANTY - springs are warranted for 1 year from purchase date