Multi-input thermal switch allows the System 1 blower to be turned on when the temperature in any of up to three zones reaches 90 degrees. The blower turns off when all zones are below that temperature. Zones are monitored by small thermal sensors on 6ft leads which can be extended. It comes with one 90 degrees sensor. In addition to multi-input capabilities the switch also allows the control of the System 1 fan without having to run switched AC power into remote locations avoiding possible wiring and fire code violations.