7-70V 30A PWM DC Motor Speed Controller, can be directly connected to the motor and adjust the potentiometer to control the motor speed. Instructions for Use and Precautions: Ensure correct polarity connection between the power supply and the controller before powering on. Reversed polarity may damage the circuit board. Do not allow wiring to touch the heat sink, as this may cause damage. For the motor connection, polarity does not need to be observed. If the motor rotates in the wrong direction, simply swap the two motor wires. Note: This is not a power supply module. It must be connected to a motor to function properly. Without a motor connected, the output will not show any change when measured with a multimeter. This controller is designed for DC brushed motors only and must not be connected to 220V AC mains power. Application in Children's Toy Cars: When used in a children's toy car, the output of the speed controller can be connected to a forward and reverse switch to enable forward and reverse operation. If the toy car already has a forward and reverse circuit regulator, connect the speed controller between the power supply and the forward and reverse regulator (i.e., before the regulator). Failure to do so may result in damage to the speed controller. Specifications: Condition: 100% new Material: Aluminum Color: Black + Green Package Contents: 1 x DC Motor Speed Controller Note: Light reflection and display differences may cause slight variations in color between the image and the actual item. Measurement may vary by +/- 1-3 cm.