For a house built in this window, the truck carries torsion springs sized for standard 7 and 8-foot residential doors, steel rollers (sealed and unsealed), lift cable, and the common opener drive parts - belt and chain, sprockets, logic boards for the more common consumer models. What we don't always carry is a part for an opener that's been discontinued for over a decade, which happens more often in a town where the original unit from a 1990s build is still running. If that's the case, we'll tell you on the spot rather than guess, and we order the part rather than force a mismatch that fails again in a year.