It is designed for control and adjust the speed of a DC motor. The output of the speed controller is DC which will not damage the governor. The applied voltage is 6V 12V 24V. Features: Use soft heat-resistant silicone line. With a reversing switch. Control the forward or reverse direction and the stop of DC motor by switch. Control and adjust the speed of a DC motor with this controller. Light weight, heavy current, wide voltage. High reliability. High efficiency, high torque, low heat generation. Specification: Working voltage: DC610V~28V Speed control range: 0%~100% Material: Plastic & Metal Item size: 6.6 * 3.1 * 1.2cm / 2.6 * 1.22 * 0.47in(L * W * H) Item weight: Approx. 32g / 1.13oz Package size: 11.8 * 7.8 * 1.5cm / 4.65 * 3.07 * 0.59in(L * W * H) Package weight: 33g / 1.16oz Package List: 1 * PWM DC Motor Speed Regulator Controller Switch Note: The package without user manual.