American Volt Adjustable Electric Radiator Fan Thermostat Switch Temperature Controller Probe Adjustable fan thermostat w/ stainless temperature probe sensor. Probe measures liquid or contact temperature and sends power to the fan. Flexible turn-on/turn-off temperature control range of 32-248'F (0-120'C). Thermostat is wired as a normally open circuit that closes when turn-on temp is reached. Probe can be mounted in between radiator fins or inside water inlet/outlet tube.