Check the listing for details. DC 4V-12V 5W XY-FS USB Fan Stepless Governor Fan Speed Controller Cooling Tool. Condition: New. Listed at 6.42 USD. Description: USB fan speed controller, USB fan adjuster. Mute multi-position wind speed regulator. Knob with switch. Strong/weak wind are free to adjust. USB fan stepless governor It is suitable for offices, dormitories, bedsides, etc. Turn the knob clockwise to increase the wind speed. Turn counterclockwise to reduce the wind speed, and the knob has a switch function. Micro USB and Male USB are input terminal which used to connect to power supply. Female USB is output which used to connect to fan. Specification: Product Name: USB Fan Stepless Governor Working Voltage: DC 4V-12V Output Voltage: DC 2.5-8.0V Rated power: 5W (Do Not Overload) Test temperature: -40~85℃ Size: 50x44x18mm/1.96x1.73x0.70 inch Package Included: 1 * USB Fan Speed Controller