USB Fan Speed Controller Why you need this - Precise airflow control for any situation where adjustable cooling matters. This controller lets you dial in anything from a gentle breeze to a strong airflow to match comfort needs or cooling requirements. - Reduces noise and power waste by allowing the fan to run at the exact speed required, instead of full power all the time. - Compact and portable design makes it easy to add variable control to USB-powered fans and small ventilation setups without bulky hardware. Key benefits and problem solving - Flexible voltage control delivers smooth, stepless adjustment of fan speed so you can fine tune airflow for comfort or component cooling. - Low-noise operation improves comfort in work and living spaces while maintaining effective cooling. - Low power consumption and high operational efficiency help extend runtime when used with power banks or limited power supplies. - Simple knob interface doubles as a power switch, giving intuitive on off and speed control in one compact unit. Main features - Input voltage: DC 4-12V to support a wide range of USB and small DC power sources. - Output voltage: DC 2.5-7.5V with stepless regulation for wide-range airflow adjustment. - Rated power: 5W. Do not overload the controller beyond this limit. - Stepless speed control for continuous adjustment from gentle to powerful breeze. - Knob operation: turn clockwise to increase speed and counterclockwise to decrease speed; the knob also functions as the power switch. - Compatibility: works with standard USB-powered fans that receive 5V directly and with two-speed USB fans that incorporate an internal boost circuit board. When a two-speed fan is set to its second gear, the fan s boost circuitry increases voltage before the motor, allowing higher airflow. - Compact mini design for easy transport and integration into small setups. - Low-noise design suitable for quiet environments. Important notes - When switching a fan to two-gear mode, set the fan to single-speed mode first to ensure proper speed adjustment. - Use the controller only within the specified input and output voltage ranges. - Package includes: Speed Controller x1. Typical applications - Personal desktop cooling: pair with a USB desk fan to control airflow for focused cooling while keeping noise low. - Portable power setups: use with power banks for adjustable cooling outdoors, during travel, or in temporary workspaces. - DIY electronics and hobby projects: provide variable ventilation for small enclosures, single-board computers, or custom cooling solutions. This speed controller provides a compact, energy efficient way to add smooth, reliable fan speed control to USB and small DC fan applications.