Wire saver module connects to "K" terminal on Honeywell Prestige thermostats, and separates into "Y" and "G" signals at furnace or air handler equipment. Intended to be used in conventional and heat pump systems requiring one wire more than is available. THP9045 wiring module is designed to be used in 1 heat/1 cool retrofit applications where only four wires are available. The K terminal on thermostat can be used to operate both fan and compressor on single wire. Module is designed to receive signal from K terminal, split signal and reroute it to operate compressor, and/or fan. For use with THX9000 Series Thermostats and T2060F3080. Mounts easily on or near HVAC equipment. Cannot be used for heat-only situation. Easy push-wire terminals provide secure lock.