Extra Air, Extra Performance Quad Air Inlet™ CRYORIG’s proprietary Quad Air Inlet™ system features four strategically placed aerodynamic air inlet that allows for extra air intake. The additional air intake allows the QF Series fan to have a higher air output volume for its fan diameter, which equals better temperatures for your CPU heatsink & more air exchanged for your system case. Pleasing Your Ears, With Acoustic Engineering QF Series PWM fans feature CRYORIG’s HPLN™ (High Precision Low Noise) bearing system, offering stable & precision rotation eliminating excess vibration & noise. Ultra Wide RPM Range, Fine Tune Your Fan Profile Featuring four pin Pulse Width Modification (PWM) RPM spin speed control, QF Series fans offer a ultra wide range of RPM settings. This wide RPM range allows users to fine tune their fan speed directly through mainboard bios settings. Roughly 33% more selection range than the system fans from competitors. *some RPM speeds are only available through PWM control. Vibration Absorbers, Included Soaking Up Every Last Bit of Noise Frame vibration causes unwanted noise. This is why all QF Series fan come with rubberized Vibration Absorbers to nullify fan vibration. Vibration Absorbers are already built directly into the fan frame, no extra work necessary.