Turn your house lights on and off from the safety of your car. This keychain remote is a small portable device that sends a signal via radio frequency (RF) to a Transceiver that is plugged into the wall. The Transceiver in turn translates the signal to Modules throughout your home to turn your lights and appliances on/off. The base transceiver receives all 16 unit numbers on a house-code -- and has a built-in appliance module.
Plug-in, wireless, battery operated transmitter, 40 feet RF range,
Lithium 3V battery
Manufacturer: X10 Wireless Technology, Inc
Manufacturer warranty: 1 year 
Product questions: 800-442-5138