Item Name: Wind Speed Controller Switch Module Wind Speed Regulator USB Fan Governor. Stepless speed regulation, free adjustment of strong wind and weak wind.Suitable for common 5.0V USB fans on the market.Knob USB fan speed controller with switch function.100% brand new and high quality.Turn the knob clockwise to increase air volume, counterclockwise to decrease air volume.Specification:Power supply range: DC 4~12VOutput range: DC 2.5~8.0VRated power: 5W (please do not overload) Fan speed regulation principle:The non-adjustable USB fan is a 5V direct-supply fan motor. The two-speed fan has a booster circuit board inside. It is placed in the second gear. The booster board increases the 5V of the USB before connecting it to the motor, and the air volume is larger.The output voltage range of the stepless governor changes smoothly between 2.5V and 8.0V, and the free air volume is set! And the scope is wider! Instructions:Plug the speed control male head into the mobile phone charger, power bank, computer USB, fan plug and then insert the speed control female head! Or use Micro USB 5.0V power supply. Precautions:Two position fan, please put the fan in the first position, otherwise it may not be able to adjust the speed! Package Included:2PCS* USB Fan Governor *Please make