PWM Electric Fan Controller. Utilizing cutting-edge technology, this controller employs Pulse Width Modulation that constantly adjusts fans speed to keep the desired engine temperature which can be preset  to meet changing needs and environmental conditions. This powerful fan control thermostat can control multiple electric fans and offers up to 65 ampere capacity to handle the toughest conditions and most powerful cooling fans available. With built-in current overload, short-circuit and overheating protection, Derale has effectively introduced original equipment reliability and function to the specialty aftermarket. With the ability to adjust fan speed from 0-100 percentage as needed, this PWM Electric Fan Controller uses variable frequency, duty-cycle modulation and active fly back snubbing for highly efficient operation. Each unit uses active input voltage regulation to achieve low EMI output.