Cryorig QF120 Balance 120mm PWM Fan 300-1600RPM CR-QFA Proprietary Quad Air Inlet system features four strategically placed aerodynamic air inlet that allows for extra air intake. HPLN (High Precision Low Noise) bearing system, offering stable and precision rotation eliminating excess vibration and noise. Four pin Pulse Width Modification (PWM) RPM spin speed control ultra wide range RPM settings. Roughly 33% more selection range than the system fans from competitors. *some RPM speeds are only available through PWM control. Integrated Vibration Absorbers built in, nullifies fan vibration. 330~1600 RPM provides a good balance between performance, RPM and noise.