Noctua"s NF-P14 fan has become a default-choice among PC enthusiasts looking for a premium quality quiet 140mm fan. the NF-A15/14 provides higher static pressure and an even better airflow/noise ratio than its much acclaimed predecessor. * The NF-A15 is tailor-made for use on today"s high-end CPU coolers: While its 150mm width matches those of most high-end heat sinks. The NF-A15"s standard 120mm mounting holes also make it an ideal performance upgrade for 120mm case or CPU fans. * The NF-A15 impeller features suction side Flow Acceleration Channels. By speeding up the airflow at the crucial outer blade regions, this measure reduces suction side flow separation and thus leads to better efficiency and lower vortex noise. * 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. * Supporting fully automatic PWM speed control, the NF-A15 PWM uses Noctua"s novel, custom designed NE-FD1 PWM IC that integrates Smooth Commutation Drive (SCD) technology which makes the fan quieter at low speeds. * The NF-A15 features the further optimized second generation of Noctua"s renowned, time-tested SSO bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilization, precision and durability.