Compatible with all Liftmaster Screw Drive and Low Profile Screw Drive operators (1995-current) Also replaces some Chamberlain models Same as Part number 25A18 Replaces sprocket couplers Use on screw drive rail assembliesReplaces sprocket coupler on screw drive rail assemblies. Compatible with all Liftmaster Screw Drive and Low Profile Screw Drive operators (1995-current), models 1000SD, 2000SD, 1000SDR, 2000SDR, 2110, 2220, and models 4600, 4620, 4640, 9902, PD420, PD460