Ultra small 3 Button Mini Remote Controller ideal for pocket, purse or key chain with rolling code technology using 433.92 Mhz Frequency. The Controller can operate up to 3 different doors and a long life 3v battery is included with all controllers. With this Mini Remote Controller no one can enter your garage but you, every time the remote control is activated, it automatically rolls the code to one of over 100 billion codes, never to be repeated again.