Patented PWM Sharing Technology (F9 PRO PWM) It shares the same PWM signal as other PWM fans being used in the system so that they all run at optimal speed based on the CPU load. Ultra Quiet The patented fan holder in combination with the anti-vibration parts (vibration absorber) ensure that the PC fan is running at a very low noise level, & thus serves as a virtually silent chassis fan option. Massive Air flow Its unique fan blades boost the volume of air flow by 20% comparing with generic case fans to facilitate efficient ventilation. Quick & Easy Installation Installation is a snap with the four screws which are included in the box. Alternatively, it is compatible with screwless mounting on the chassis (if applicable).