Chamberlain 740CB Wireless Keyless Entry System For use with older Chamberlain garage door openers (390 MHz only) Billion code technology assures one of over 10,000 changeable codes is sent every time the keypad is used Completely wireless  powered by one 12-Volt battery (included) Weatherproof flip-up protective cover Backlit keypad makes numbers easy to see, even in the dark. Programs in 2 easy steps