Superior Material: Made from durable PC+metal for long-lasting use. Package Contents: 3-pack fan DC control module. Stepless speed regulation output voltage range in 2.5V-8V stable change, so that the fan wind speed can be adjusted, which greatly improves comfort. PWM DC Motor Control Specification: Power supply range is DC 4~12V, rated power is 5W (overload is not allowed). The current in the same product is up to 5A. Potentiometer with switch function. Instructions for use: Insert the regulator into the phone charger or charging source, insert the fan's USB connector into the regulator's USB port, and then turn the adjustment knob to adjust the small air volume and the large air volume. Turn the knob clockwise to increase the air volume. Turning it counterclockwise makes the air volume softer, and the knob has a switching function. A Wide Range of Applications: Suitable for speed regulation of DC motor, fan, aquarium oxygen pump and other products. Color: as shown Package Contents: 3 * Fan Air Volume Speed Regulation Module Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowable measurement error is +/- 1-3cm.