Item Type: USB Fan Speed Controller_x000D_ Product Material: Printed Circuit Board_x000D_ Power Supply Range: DC 4~12V_x000D_ Output Range: DC 2.5~ 8.0V_x000D_ Rated Power: 5W_x000D_ Function: Stepless speed regulation on fan speed. 1With this USB fan speed control module, you can easily adjust the USB fan speed for more efficient heat dissipation. 2The output voltage of the stepless speed regulator changes smoothly between 2.5V-8V, making the adjustment easier. 3You can turn the knob clockwise to increase the air volume, you can also turn anticlockwise to make the air flow softer. 4The knob has switch function, so the operation is very easy, and the simple installation can be quickly completed as well. 5Adopting premium Printed Circuit Board, the USB fan speed control board is very durable for long-term use.1 x USB Fan Speed Controller