Noctua NF-S12A PWM, 4-Pin Premium Cooling Fan (120mm, Brown) Award-winning third-gen 120x25mm S12 fan with Anti-Stall Knobs and Advanced Acoustic Optimisation frame for superior quiet cooling performance Airflow-optimised design for highly efficient, near-silent ventilation of PC cases and other chassis (intake & exhaust), cabinet cooling, etc. 4-pin PWM version for automatic speed control via 4-pin PWM fan headers, broad 300-1200rpm speed range (900rpm max. with supplied Low-Noise Adaptor) Includes anti-vibration mounts, fan screws, Low-Noise Adaptor, extension cable and y-cable for running two PWM fans on the same header The NF-S12A features the third evolution of Noctua's classic Straight Blade Design that achieves 10 cfm The NF-S12A's Anti-Stall Knobs reduce flow separation phenomena in medium to high impedance situations n thereby increase the fan's stall margin, that is even more versatile than its renowned predecessor . Noctua's AAO (Advanced Acoustic Optimization) frames feature integrated anti-vibration pads as well as Noctua's proprietary Stepped Inlet Design and Inner Surface Microstructures, both of which further refine the fan's performance/noise efficiency. Noctua's Stepped Inlet Design adds turbulence to the influx to facilitate the transition for laminar flow to turbulent flow, that reduces tonal intake noise, improves flow attachment, incur suction capacity, especially in space restricted environments. Integrated Anti-Vibration Pads made from extra-soft silicone minimize the transmission of minute vibrations while maintaining full compatibility with all standard screws and other mounting systems. Low-Noise Adaptor (L.N.A.) 4-Pin Y-Cable 30cm Extension Cable 4 Vibration-Compensators 4 Fan Screws