18TR Garage Door Remote Control for Garage Door Opener is an efficient system to remotely control your Garage Door. It is a combo unit consists of two basic operating devices: One 18T Keychain Transmitter and one 18R Garage Door Receiver. When you need to open your garage door, just press a button of the Transmitter to enliven the mediator Receiver Unit to activate the Garage Door Opener System connected with the Receiver. With this Compact-size dual button transmitter, you have the flexibility of operating two garage doors simultaneously with help of an additional Receiver unit. Also you can customize it with SW-18R Wireless Switch Receiver Unit to turn on/off lights, fan and small appliances.