Material: USB Fan Governor is made of electronic accessories element, inner conductor is pure copper. it is long lasting and durable for you to use. | Rated Power: 5W (please DO NOT overload use), Suitable for common 5.0V USB fans | USB Fan Speed Controller: The wind speed of the fan can be adjusted between 2.5V to 8V according to your comfort | Directions for use: Insert the governor into the phone charger or charging treasure, insert the fan USB plug into the USB port of the governor, and then turn the adjustment knob to adjust the small air volume and large air volume. Turn the knob clockwise to increase the air volume. Turning it counterclockwise will make the air volume gentler and the knob has a switch function. | Package including: 3 pcs * USB Fan Speed Governor