Liftmaster 41c4220a Gear and Sprocket Kit for Chamberlain, Sears, Craftsman and LiftMaster 1/3 and 1/2 HP Chain Drive Models Includes: Gear and sprocket, worm gear, grease, motor shaft bearings, sprocket bearings, instructions Compatible with chain drive chamberlain sears craftsman manufactured operators 1984-current Compatible with chamberlain, sears, craftsman and lift master 1/3 and 1/2 HP chain drive models Verified 100% authentic OEM lift master product- new production dates Easy DIY- complete assembly