Feature: Soft start can solve the damage caused by instantaneous high current to speed controller. Blocking protection(20A current limited) can limit the high current produced by the blocking of the motor. Panel switch control makes it more easy to control the speed. Ultra-high power control. The maximum current is 20A. It is recommended not to exceed it. With low voltage and stall/over-current protection. Specification: Input voltage: DC 10-60V (The specific voltage must be the same as the rated voltage of the motor) Output voltage: Linear output under load Current: 0-20A (Limited value 20A) Regulating type: regulating current Regulating method: potentiometer(270 linear) Regulating speed range: 0-100% Control frequency: 15KHZ Knob: 10K(with switch) Size: Approx. 9.6 x 6.1 x 3.4cm / 3.78 x 2.4 x 1.34inch Weight: 107g Package Included: 1 x DC Motor Speed Controller Note: The input terminal must be divided into positive and negative input. The input voltage must be the same as the rated voltage of the motor(within DC 10-60V). Can not input AC 220V, or it will burn up the module directly. Blocking protection is not a power cut, it is the limited current value of 20A. Please allow 1-3cm differences due to manual measurement. Thank you for your kindly understanding.