With this cable it is possible to operate a fan simply via an USB connection The voltage is just right to operate a fan quietly and with a pleasant airflow When looking into operating a fan outside of the system enclosure and the hot summer months are coming up This is the perfect solution to quickly make a computer fan into a desk fan! Features - One end is 4 pin chassis fan header,and another end is the computer USB port - Chassis fan must support low-voltage 5V to start because USB voltage is 5V - The cable can convert USB 5V into 12V for computer PC fan use Note - When using the chassis fan with USB interface as power supply - The fan speed maybe be reduced to more than half the original speed