Noctua NF-B9 redux-1600 PWM, 4-Pin, High-Performance Cooling Fan with 1600RPM (92mm, Grey) Renowned NF-B9 high-end 92x25mm 12V fan, more than 100 awards and recommendations from international computer hardware websites and magazines, hundreds of thousands of satisfied users Highly optimised low-noise design with outstanding quietness of operation, static pressure and airflow (CFM), ideal for chassis ventilation, cooling fan replacement for NAS and other devices, etc. 1600rpm 4-pin PWM version with excellent balance of performance and quietness, supports automatic motherboard speed control (powerful airflow when required, virtually silent at idle) Streamlined redux edition: proven Noctua quality at an attractive price point, wide range of optional accessories (anti-vibration mounts, S-ATA adaptors, y-splitters, extension cables, etc.)