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 and more air exchanged for your system case. QF Series PWM fans feature CRYORIG’s HPLN (High Precision Low Noise) bearing system, offering stable and precision rotation eliminating excess vibration and noise. 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.