ITEM NAME:USB Fan Speed Controller DC 4V-12V 5W Multi-Gear Mute Auxiliary Cooling Tool Pg Features: New and high quality -USB fan speed controller.Mute multi-position wind speed regulator.It is suitable for offices, dormitories etc.. -DC 5V for the non-adjustable USB fan.Boost board inside the fan for the two-position fan.This boost board step up voltage for motor in fan when in the second gear.Causes the fan to turn faster and the wind becomes bigger. Working Voltage:DC 4V-12V Output Voltage:DC 2.5~8.0V Rated power: 5W(Do not overload!) Test temperature: -40~85℃ Physical dimension:50*44*18mm Package include: 1 x USB Fan Speed Controller.Rated power: 5W(Do not overload!).