Variety usedUsed for receiver, cabinet, DVR, playstation, TV box, fridge, incubator, aquarium,ham radios and more that requires cooling or ventilation; or as a replacement fan. Silent Each computer case fan equipped with 4 silicone rubberfeets, which can help absorbing the air flow shock and absorb the noise,reduce to 9.3-16.8dBA. L/M/H 3-Degree Speed Controller The variable speed is great for turning the speed up or down to your noise comfort level. It is cycles from high-Medium-low and off speed mods. Convenient The fan is suitable for devices with a USB interface, No matter where you are, just plug it in and use it. Dual ball bearings Durable dual ball bearings have a lifespan of 50,000 hours, and allow the fan to be flat or upright and easy to use.