The Multi-Code 109020 300 Receiver is normally used with residential garage door openers. The receiver mounts directly to the three terminals on the door opener with terminal lugs that fit under the terminal screws. It has a 11-inch wire antenna attached to the receiver and your opener supplies the 24-volt power to the receiver. When the power is not supplied to the receiver can use an optional separate 24-volt ac plug-in transformer. The receiver is programmed using a 10-position coding switch. When a Multi-Code type transmitter(s) is set to the same code it activates the receiver to trigger the door operator. Includes Programming instructions.