3PCS 5W USB Fan Speed Controller, DC 5V to DC 4-12V to 2.5-8V Continuous USB Fan Regulator Speed Control Knob with Switch

★Material: The USB fan controller is made of electronic components; the internal conductor is pure copper, making it durable and long-lasting.
★Rated Power: 5W (please do not overload), suitable for common 5.0V USB fans.
★USB Fan Speed Controller: The fan speed can be adjusted between 2.5V and 8V as needed.
★How to Use: Plug the controller into a phone charger or power bank, plug the fan's USB connector into the controller's USB port, and then turn the adjustment knob to set the airflow for low or high speeds. Turn the knob clockwise to increase airflow, and counterclockwise to decrease it. The rotary knob also functions as a speed switch. ★ Package includes: 3 pieces * USB Fan Speed Controller