Features: Using PWM speed control technology, with high conversion efficiency, wide speed range, and stable performance. Adopting imported semiconductor chips and testing voltage, current, function, etc. The circuit is stable and reliable. Overload short circuit protection and current no more than 30 seconds. The potentiometer is used to accelerate the positive and negative switch forward, backward and stop. Specifications:Resistor Resistance Value: B10KDecable Length: Approx. 20cm/7.87''Resistor Mounting Hole: 8mmVoltage: DC 10V-30V (Wide Range)Working Voltage: 12v*3A=36W/24V*3A=72W Maximum Up to 120WPrated Weight: 3A(Maximum Continuous Output Current)Maximum Current: 4A Modulation Range: 5%-95%PWM Frequency: 500HZComper Size: Approx. 74*47*28mm/2.91*1.85*1.10''Net Weight: Approx. 66gGross Weight: approx. 70gNote:1. DC motor speed control, the input is DC, you can not directly connect AC current (such as 220V AC), otherwise it will burn.2. The positive and negative poles of the DC power supply cannot be reversed, otherwise the regulator will be damaged.3. The motor can be divided into positive and negative, when the operation direction and expectations are inconsistent, the alignment direction can be changed.4. The potentiometer knob can change the output duty cycle of the regulator, thereby changing the speed of the motor.5. Please allow 1-3mm differs due to manual measurement.6. Due to the different display and different light, the picture may not reflect the actual color of the item. Thank you for your understanding.1 x DC1 Motor Speed Controller.