The Wireless Relay Plus is the perfect solution when you can't run wire or existing wires have been cut or damaged. The Wireless Relay communicates wirelessly up to ¼ mile between two devices via a 915MHz radio frequency. The Wireless Relay Plus contains 2 four-channel transceivers. The base module has 3 transmitting channels and 1 receiving channel. The satellite module has 3 receiving channels and 1 transmitting channel. The relays can be used to control or monitor heat pumps, condensing units, fans, pumps, lighting, and industrial equipment. Factory-paired, multiple pairs can be installed in same building.