Size: 433 MhzThe 433 MHz 2 Channel receiver (433ESREC) has the ability to control two separate devices or two different relays on a control board and can learn up to 400 codes. The typical situation for the receiver controlling two devices in in a 3 car garage. Usually there are 2 separate garage door openers in this type of garage and you can utilize the one receiver to control each one of them with a separate button on the remote. Another option for using the two relays on the receiver is controlling two separate terminals on a single gate opener. Many times gate openers will have a terminal for an automated open and close and another terminal for partial opening or open only during re-closing without stopping. A second button on the remote could be used to control this second function.