The 977LM is a wireless keyless entry system for garage door openers with Security+ Anti-Burglary Coding. Mount it to your garage door jamb with two screws for keypad access without a remote control. The rolling code technology changes with each use to prevent code grabbing, generating over 100 billion possible codes. Compatible with garage door openers manufactured from 1997 to present. Supports temporary access codes for guests, service personnel, and family members. Works with Chamberlain remote models 950CB, 953CB, and 956CB.