Description: This is a simple and easy-to-use DC motor speed controller with small size, elegant appearance and stable performance. It is manufactured with high quality circuit board which ensures a longer lifespan. It supports soft start, locked rotor protection, low voltage protection. Features: The speed controller is manufactured with high quality circuit board which ensures a longer service life. This simple and easy-to-use DC motor speed controller has stable performance. This motor speed controller uses screw terminals for convenient and quick wiring. The soft start function would protect the speed controller and motor from damage caused by large instantaneous current. It supports locked rotor protection by limiting large current (maximum 30A) instead of cutting off the power. If you use storage battery as power supply, the low voltage (10V) protection function would prevent over-discharging. 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) Frequency control: 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