Chamberlain 940D Wireless, Keyless Entry System, 315 MHz Security plus wireless keyless entry system Open and close the garage door without a remote control or keys using a private 4-digit password Designed for openers built since 2005 Mounts conveniently outside garage, backlit for night-time use, and includes flip-up cover for protection from the elements 315-megahertz and operates off of 12-volt battery