It's a PWM speed controller so it enables you to control the speed of these little DC brush motors smoothly. It's ideal for applications like fans, etc. providing nice adjustment of motor speed instead of the more usual "High-Low" switching. Features: Wide range of operating voltage: 12V, 24V, 36V, 60V, max. power: 400W. A good speed controller for DC brush motors. High-frequency capacitance, power tube and 10A fuse are used in the module. Adopts sealed and high-quality potentiometer with switch, stable performance. Metal case creates better durability; high efficiency and low noise. Suitable for applications like fans, etc. providing nice adjustment of motor speed. Notice: 1. This speed controller is applicable to DC brush motor, not the DC brushless motor; it can't be used as voltage regulator. 2. It should be connected with DC voltage, don't connect with AC voltage(e.g. 220V AC). 3. The anode and the cathode of DC power cannot be connected reversely, otherwise the controller will be damaged. 4. When running direction is inconsistent with your desire, you can change it by adjusting the linear order. 5. Potentiometer switch can change the output duty cycle of controller and then change the motor speed. Specifications: Operating Voltage: DC 12V/24V/36V/60V Rated Current: 8A Max. Current: 10A Control Power: Max. 400W Speed Control Range: 10% -100% PWM Frequency: 21KHz Item Size: 90 * 40 * 3mm / 3.54 * 1.57 * 1.18in Item Weight: 79g / 2.8oz Package List: 1 * DC Motor Speed Controller