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. Incorrect connection may damage the circuit board. Do not allow wiring to touch the heat sink, as it may cause damage. For the motor connection, polarity does not need to be observed. If the rotation direction is incorrect, simply swap the two motor wires.Note: This is not a power supply module and must be connected to a motor to function properly. Without a motor connected, the output 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 mains power.Application in Children's Toy Cars: If used in a children's toy car modification, the output of the speed controller can be connected to a forward/reverse switch to enable directional control. If the toy car already has a forward/reverse circuit, ensure the speed controller is installed between the power source and the forward/reverse circuit (i.e., before the existing forward/reverse switch). Failure to do so may result in malfunction or damage.Specifications: Condition: New Material: Aluminum Color: Black + Green Package Contents: 1 x DC Motor Speed Controller (Other items not included)Note: Lighting effects and monitor settings may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3 cm.