The 41C4220A is comptabile with: Liftmaster Sears Craftsman Chamberlain Access Master and all other Chamberlain Chain Drive Units manufactured after 1984. You can find the manufacture date on the back of your motor unit.
Not sure if your garage door opener is compatible with the 41C4220A? Check the manufacture date on your motor head. Does your current chain drive gear have a diameter of 2 3/4" and a bore diameter of 1/2"? Does the sprocket assembly look the same?
41C4220A includes: Sprocket and drive gear, worm gear, grease, replacement bearings, and instructions.