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 between the power supply and the controller before powering on. Incorrect connection may damage the circuit board. Do not touch the heat sink during wiring, as it may cause damage to the circuit board. For the motor connection, polarity does not need to be observed initially. 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 voltage will not change when measured with a multimeter. This controller is designed for DC brushed motors only and must not be connected to 220V AC household power. Suitable for use with children's toy cars. If used in a children's car modification, connect the speed controller’s output to a forward/reverse switch to enable forward and reverse control. If the children's car already has a forward/reverse circuit regulator, connect the speed controller between the power source and the forward/reverse regulator (i.e., before the regulator). Failure to do so may result in damage to the speed controller. Specifications: Condition: Material: Aluminum Color: Black + Green Package Contents: 1 x DC Motor Speed Controller Note: Light reflection and differences in display screens may cause slight variations in color appearance. Measurement allows an error of +/- 1-3 cm.