Features Simple and easy to use: The DC motor speed controller is small in size, beautiful in appearance, and simple in performance. It is made of high-quality circuit boards to ensure a longer service life. Screw terminal block: This motor speed controller adopts screw terminal block, which is convenient and quick to connect. The knob is 10K (with switch), and the speed range is from 0% to 100% Support soft start: Brush motor speed governor supports soft start, locked-rotor protection, low voltage protection, soft start function can protect the governor and motor from damage by large instantaneous current Locked-rotor protection: The overload protection board supports locked-rotor protection by limiting the large current (maximum 30A) instead of cutting off the power supply. The adjustment method adopts potentiometer, linear, 270° Low voltage protection function: The adjustable speed board has a low voltage protection function. If a battery is used as a power source, the low voltage (10V) protection function can prevent over-discharge Description: This is a simple and easy-to-use DC motor speed controller of small size, elegant appearance and stable performance. It is made with high quality circuit board which ensures a longer service life. It support soft start, locked rotor protection, low voltage protection. Features: Speed controller is made with high quality circuit board which ensures a longer service life. This simple and easy-to-use DC motor speed controller has an stable performance. This motor speed controller uses screw terminals for convenient and quick wiring. Soft start function would protect speed controller and motor against damage from large instant current. The overload protection board supports locked rotor protection by limiting large current(maximum 30A) instead of cutting off power. If you use a storage battery as power supply, the low voltage(10V) protection function would prevent over-discharge. Specifications: Input Voltage: DC10V-55V Output Voltage: Linear with load Output Current: 0A-40A Limit Current: 30A Speed Range: 0% to 100% Regulation Method: Potentiometer(Linear, 270°) Control Frequency: 15KHz Wiring Type: Screw terminal Rotary Knob: 10K(with switch) Size: 80 x 56 x 28mm / 3.15 x 2.2 x 1.1" Package Includes: 1 x Speed Controller Package List