Features: Directions for use: Insert governor into phone charger or charging treasure, insert the fan USB plug into the USB port of governor, and then turn the adjustment knob to adjust the small volume and volume. Turn the knob clockwise to increase the volume. Turnings it counterclockwise will make the volume gentlers and the knob has a switches function. Motor Governor specification: The supply ranges is 4~12V, rateds is 5W (Do not overloads). The current in the product is up to 5A. Potentiometer with switches function. Super material: It is made of PC+metal. it is long lasting and durable to use. Package including: of fan governor module. Stepless speed regulation output voltages ranges in 2.5V-8V stable change, so the wind speed of the fan can be adjusted, greatly the comfort. A wide ranges of applications: It is suitable for the speed regulation of motor, fan, fish tanks oxygen pump and other . Specifications: Material:Plastic Size:Approx.50x36mm/1.97x1.41" Package Includes: 1 Piece Speed Controller note: Please allow 1-2cm errors due to manual measurement,Please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.