Insteon 24950A7 I/O Linc High and Low Temperature Threshold Kit Sensor mounts on the interior or exterior of your home to monitor temperature Adjustable high and low temperature set points between -30 F and 130 F Once a threshold has been reached, the sensor contacts open sending a signal to the I/O Linc Once signaled, I/O Linc will trigger Insteon-controlled lights or appliances to turn on High/Low temperature sensor is completely mechanical and requires no power supply