This ultra-quiet USB cooling fan is designed to economically cool DVRs, video game consoles, cable boxes, modems, computers, amplifiers, and other audio video equipment. The fan includes an in-line multi-speed controller with power switch to set the fan’s speed to optimal noise and airflow levels for various environments. The USB plug can be plugged into the USB ports and for more airflow upto four can be daisy chained to share the same power source.