LiftMaster 850LM Universal Gate and Garage Door Opener Receiver Compatible with 811LM, 813LM, and all MAX remote controls Expands to three channels: Channel 1 - 50 remotes, Channel 2 - 20 remotes, Channel 3 - 20 remotes Compact design fits most gate and commercial door operators Provides convenient access to gated communities, industrial facilities, and commercial sites all with a single transmitter solution Multiple remote control options available to provide secure access from the safety and convenience of a vehicle