Features 1、With this USB fan speed control module, you can easily adjust the USB fan speed for more efficient heat dissipation. 2、The output voltage of the stepless speed regulator changes smoothly between 2.5V-8V, making the adjustment easier. 3、You can turn the knob clockwise to increase the air volume, you can also turn anticlockwise to make the air flow softer. 4、The knob has switch function, so the operation is very easy, and the simple installation can be quickly completed as well. 5、Adopting premium Printed Circuit Board, the USB fan speed control board is very durable for long-term use. Specification Item Type: USB Fan Speed Controller Product Material: Printed Circuit Board Power Supply Range: DC 4~12V Output Range: DC 2.5~ 8.0V Rated Power: 5W Function: Stepless speed regulation on fan speed. Package List 1 x USB Fan Speed Controller