The Sentry Garage Door Receiver easily connects to your garage door opener allowing your Sentry 2 button trasmitter, Push to Operate button or Wireless keypad to control your garage door. This recevier operates at 433 mhz and is compatible with all USAutomatic transmitters. The kit contains receiver, transformer and a wire harness that easily installs to the existing garage door. All existing transmitters used for garage door will continue to operate they are not being disconnected. One receiver per garage door is required.