Shuts down your electric cooling fan above 50-60 MPH for improved engine cooling. In vehicle testing, we have seen a ten degree drop in engine temperatures while operating above 60 MPH. Prevents the electric fan from fighting airflow through the radiator at highway speeds. The unit is adjustable and may be overridden by using the supplied dash mounted toggle switch. This kit is designed to be used with the supplied signal generator that is installed into the speedometer cable. Actual unit may vary in appearance from photo.