The DC motor speed controller allows the use of pulse width modulation (PWM) and a fully adjustable positive DC and negative DC output with a duty cycle between 0% and 100% to control the speed and direction of the DC motor The circuit also includes whose brightness varies in proportion to the relative speed of the motor, so Provide visual feedback of current speed. Overload and short circuit protection current is 10A PWM frequency: 16kHz Adjustable duty cycle: 0-100% Power-on LED indicator Working environment temperature: -20-40 The forward and reverse switch is used to control the direction and stop of the motor. Speed can be adjusted by external 0-5V signal Note: This cannot be used for brushless motors. The controller does not have reverse polarity protection. If you connect the power supply with the wrong polarity, the controller will be damaged. Before turning on the power, check all connections carefully and always turn off the power before changing any wiring. Material:plastic colour:green Package Contents: 1 x 6 - 30V 6A DC Motor Speed Controller Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.