USB Fan Speed Governor — Stepless 2.5V–8V Controller What it does Smooth, stepless speed regulation with a stable output voltage range of 2.5V–8V. Adjust fan speed precisely to match your comfort needs without sudden jumps. Converts any ordinary USB fan into a customizable cooler by controlling the fan’s input voltage. Key benefits Better comfort: fine-grained control lets you find the optimal airflow and noise balance for working, studying, or sleeping. Simple, reliable operation: plug the controller between a USB power source and the fan, then turn the knob to set the speed. Portable and compatible: works with standard USB-powered fans and common USB power sources (power banks, phone chargers, laptop USB ports). Features and specifications Output voltage range: 2.5V–8V (stepless). Provides stable voltage adjustment across the full range. Operation: rotary knob — clockwise to increase speed, counterclockwise to decrease. Input: USB. Construction: durable ABS housing for lightweight, impact-resistant use. Interface: plug-and-play—no software or batteries required. How to use 1. Insert the controller’s USB plug into a USB power source (for example, a power bank or USB charger). 2. Insert the fan’s USB plug into the controller’s USB port. 3. Turn the adjustment knob clockwise to raise fan speed, counterclockwise to lower it. Practical use scenarios At your desk: connect to a laptop or USB charger to dial in quiet, focused airflow while you work. In a dorm room: use with a power bank or wall adapter to keep a small USB fan at a comfortable setting without full power. While traveling: plug into a portable power bank on buses, trains, or in hotel rooms to customize cooling without bulky adapters. Why choose this controller Precise stepless control (2.5V–8V) for smoother adjustments than basic on/off or multi-step controllers. Durable ABS construction and a straightforward rotary interface make it dependable and easy to use. Broad USB compatibility makes it a practical accessory for any USB-powered fan.