LIFTMASTER Garage Door Openers 41A5434-13 Belt 8' Door Full belt assembly for use with LiftMaster belt drive models 2500, 2580, 2280, 3500, 3580, 3280. Full belt assemby for use with Chamberlain belt drive models WD822K, WD922K, WD912K. For standard 8 foot high garage doors. "T"-Rail assembly ONLY. Also part number 001A5434-13A. Belt length end to end 255".