041C4398A. RPM Sensor Replacement Kit. For use with various LiftMaster® and Chamberlain® Garage Door Openers; featuring a 5-bladed photo interrupter sensor; manufactured after 1997 only. Check the owner's manual or replacement parts diagram for specific part information before ordering to ensure compatibility.  Came fro a Chamberlain Liftmaster Professional 1/3 HP Garage Door Opener, Model 1345.  Used.  Fully functional.