Wide Application: 2 fans with speed controller; Designed to Cool external HD, receivers, modems, routers, DVRs, mini PC, video game consoles, computers, amplifiers, various electronics and components; Ventilate microgreens, Move Air in orchid/reptile terrarium; Circulate Air in AV cabinet with limited ventilation, or as an Exhaust fan for soldering station Computer Fan with AC Plug: They have a power supply to attach to 110v which converts to 12v DC, you don't have to do any special wiring to get them to work; it has multiple options for mounting, you can choose to use it with the rubber feet or not Adjustable Speed: an variable speed controller with fine tuning knob allows you adjust the fans speed from 1400 rpm to 3500 rpm to get the desired amount of air flow and noise level; the cords is long enough 7.7ft to reach different spots; Just plug the AC Plug into 110 volt outlet to start the fan Small Footprint Saving Space:Fan Size: 6.3 x 3.2 x 1.0 inches (160 x 80 x 2