It's a PWM speed controller which enables you to control the speed of those DC brush motors smoothly. It's ideal for applications like car motors, DC heater, bulb etc. providing nice adjustment of motor speed. Features: Wide voltage range, 10-50V, 40A, max. 2000W for motor speed control And HHO. Apply PWM Modulation system to adjust motor speed from 5-100 . Stable in working, high efficiency and low noise. Field-effect tube, drive IC, 70m copper sheet PCB for higher efficiency of PWM wave output. Potentiometer for speed adjustment, protective case creates better durability. Specific Power Control: 12V: 480W; 24V: 960W; 36V: 1440W40V: 1600W; 50V: 2000W PWM Working Principle: BY changing the duty ratio of square wave(output) to adjust average current power from 0-100% on load, thus to change the motor speed or light brightness. Main Applications: 1.Universal DC brush motor speed control. 2.Control motor speed of cars(eg. car cooling fan motor, car fan motor, car windshield wiper motor, air condition fan motor) 3.Adjust speed of the conveyor of product lines, tube exhaust fan, treadmill, electric fan. 4.Adjust temperature of DC heater, brightness of common DC bulb. Specifications: Type: Potentiometer(1) / Potentiometer with External Wire to connect(2) (Optional) Working Voltage: DC 10-50V Control Power: 0.01-2000W Rated Current: 40A Quiescent Current: 0.025A PWM Duty Ratio: 5-100 PWM Frequency: 12khz Working Temperature: -20 to 40 Item Size: 10 * 5 * 2.7cm / 3.94 * 1.97 * 1.06in (Type 1) Item Size: 9 * 5 * 2.5cm / 3.54 * 1.97 * 0.98in (Type 2) Wire Length: 18.5cm / 7.28in (Type 2) Item Weight: 92g / 3.25oz(Type 1) 97g / 3.42oz(Type 2) (Without Cover Package Size: 10.3 * 5.3 * 3.5cm / 4.06 * 2.09 * 1.38in Package Weight: 139g / 4.9oz(Type 1) 142.5g / 5.03oz(Type 2) Package List: 1 * DC Motor Speed Controller