Wireless Transmitter and Receiver may be used to connect any contact sensor wirelessly. Transmitter accepts a Normally open or Normally closed contact input. Receiver has a 4 zone relay output that may be wired to 4 independent inputs of your Sensaphone or grouped together to one or more inputs. Program as many as 4 transmitters to one receiver for actual zone recognition on the dialer. Amazing 3000' range over open ground.