The output of the speed controller is DC which will not damage the governor. The applied voltage is 9-50V. Adopt imported special speed drive IC. Thickened copper sheet and PCB balanced arrangement of heavy current make the output of PWM high-efficient. Features: New generation of 9-50V 40A DC Motor Pump Speed Controller 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 Thickened copper sheet and PCB balanced arrangement of heavy current Specification: Operating voltage: DC10V-50V Controlled power: 0.01-2000W Quiescent current: 0.025A PWM duty cycle: 5 percent - PWM frequency: 12khz Working Temperature: -20-40 Material: Metal and Plastic Item size: 12.2 x 5.5 x 3.8cm / 4.8 x 2.17 x 1.5in(L x W x H) Item weight: Approx. 137g / 4.83oz Package size: 20 x 14.7 x 4cm / 7.87 x 5.79 x 1.57in(L x W x H) Package weight: 138g / 4.87oz Package List: 1 x PWM DC Motor Speed Regulator Controller Switch Note: The package without user manual. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.