Chamberlain 41C4220A LiftMaster Gear & Sprocket Assembly Kit Includes: Gear and sprocket, worm gear, grease, motor shaft bearings, sprocket bearings, instructions Compatible with chain drive chamberlain sears craftsman manufactured operators 1984 Compatible with chamberlain, sears, craftsman and lift master 1/3 and 1/2 HP chain drive models Verified 100% authentic OEM lift master product Easy DIY complete assembly product