Features: Inputs are powered by standard USB-A plugs (5V voltage)Output voltage adjustable from 2.5V to 8V (0.5V) according to the knobSuitable for all kinds of USB-powered small devices for voltage regulation, such as USB fans, USB LED lights and so on.Turn the knob clockwise to increase the speedTurn the knob counterclockwise to reduce the speedTurn counterclockwise to close the outputTo avoid serious heat, it is recommended that the output power is controlled within 7WMaterial: PLAcolour: BlackPackage Contents:1 x USB Speed ControllerOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.