The NF-A12x25 is a highly optimized next-generation 120mm fan that integrates Noctua's latest innovations in aerodynamic engineering in order to achieve an unprecedented level of quiet cooling performance. It takes state-of-the-art technologies such as the AAO (Advanced Acoustic Optimisation) frame or Flow Acceleration Channels and combines them with a record tight tip clearance of only 0.5mm, which is made possible by using the novel Sterrox® liquid- crystal polymer (LCP) compound as well as a metal-reinforced motor hub and axis for ultimate precision. Following the approach of Noctua's A-series, the NF-A12x25 is a true all-rounder that yields superb results in all types of usage, regardless of whether it's in low-impedance, airflow-oriented applications such as case cooling, or high- impedance, pressure-demanding scenarios such as on heatsinks and watercooling radiators. The 3-pin ULN version provides super-slow 1200/900rpm speed settings for ultra-low-noise applications and highly noise-sensitive users who demand near-silent acoustics. Topped off with exceptional running smoothness, Noctua's reference-class SSO2 bearing, a rich bundle of accessories and 6-year manufacturer's warranty, the NF-A12x25 is a premium-quality product through and through. Its superior efficiency, cutting-edge construction and pioneering materials make it an elite choice for the most discerning demands.Next-generation performanceNoctua's 120mm fans such as the NF-F12 and NF-S12A are renowned as being among the best on the market and have received more than 400 awards and recommendations from the international press. With its further improved efficiency and novel, state-of-the-art engineering, the NF-A12x25 represents another step up in performance and manufacturing.Highly optimized P/Q curve for all applicationsThe NF-A12x25's sophisticated aerodynamic design allows for a pressure to airflow (P/Q) curve that is extremely strong in the critical mid-section. This ms that the NF-A12x25 is a true jack-of-all-trades with excellent performance in both static pressure demanding and airflow demanding applications.Excellent on-application acousticsWhile many fans produce unpleasant, high-pitched noises when installed in typical applications such as on heatsinks or radiators, the NF-A12x25 has been carefully fine-tuned for optimal on-application acoustics. It produces a smooth, pleasant frequency profile and surprisingly low sound pressure levels (SPL) when working against back pressure.Flow Acceleration ChannelsThe NF-A12x25 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.Ultra-tight tip clearanceThe NF-A12x25 has a record tight tip clearance (distance between the blade tips and the inside of the frame) or only 0.5mm. This highly ambitious design sets a new benchmark for 120mm fans and helps the NF-A12x25 to work more efficiently against back pressure, such as on heatsinks or radiators, by reducing leak flows through the gap between impeller and frame.Metal-reinforced motor hubThe centrepiece of the NF-A12x25's motor hub is made entirely from steel and the axle mount is reinforced with an additional brass structure. In combination, both measures ensure ultimate precision and increased stability in the critical hub area.Sterrox® liquid-crystal polymer compoundThe NF-A12x25's impeller is made from Noctua's novel Sterrox® liquid-crystal polymer (LCP) compound that features extreme tensile strength, an exceptionally low thermal expansion coefficient and damping characteristics that are ideal for reducing resonance and vibration phenomena in advanced fan-blade designs.AAO frameNoctua'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.Stepped Inlet DesignNoctua's Stepped Inlet Design adds turbulence to the influx in order to facilitate the transition from laminar flow to turbulent flow, which reduces tonal intake noise, improves flow attachment and increases suction capacity, especially in space-restricted environments ts.Inner Surface Microstructures With the tips of the fan blades ploughing through the boundary layer created by the Inner Surface Microstructures, flow separation from the suction side of the blades is significantly suppressed, which results in reduced blade passing noise and improved airflow and pressure efficiency. Integrated anti-vibration padsIntegrated anti-vibration pads made from extra-soft silicone minimize the transmission of minute vibrations