This kit is designed to control an electric fan such as a Davies Craig Electric Cooling Fan, Part No. 1591-001 (sold separately). The controller can be set to turn on the fan at any temperature between 40°C and 100°C (104°F - 212°F). The low-profile probe slips into a radiator hose (no adapter required), and the controler gets spliced into the power wire to your fan relay. Works with 12v to 24v DC power.