The Dual Button Keychain Remote is a great accessory for any Mighty Mule Gate Opener. ThIs Remote is ideal for a replacement or additional user to compliment any Mighty Mule Gate Operator. The Remote features a compact key chain design for easy portability. Use on up to two different applications, including automatic gate openers and garage door openers. An unlimited number of transmitters can be utilized by simply adjusting the code on the Remote to match your existing system. Garage door openers require the Universal Garage Door Receiver (RB709U-NB) Size: 3.9 In.