If you have a security/home automation setup in your home, you can easily add wireless RF control to almost any device. 2-Button 3-Channel RF T315 MHz RF Transmitter can send a signal to a receiver up to 500 feet away. The transmitter must be used with a 1-Channel, 2-Channel or 4-Channel RF Receiver (each sold separately) to unlock and secure doors, control house lights or garage doors, and/or signal your alarm panel. The 2-Button, 3-Channel RF Transmitter and receiver system is extremely secure, with over 68 billion possible fixed codes. A keychain ring is included.