Noctua NF-A6x25 FLX 60mm Blæser

Noctua NF-A6x25 FLX 60mm. Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua’s AAO frame, the NF-A6x25 FLX is a highly optimised, premium quality quiet fan in 60x25mm size.
Flow Acceleration Channels.
The NF-A6x25 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.
Reduced Motor Hub Size.
Thanks to its streamlined, compact motor design, the NF-A6x25’s motor hub is smaller than with conventional 6cm fans. This allows for more blade surface area and thus contributes to the NF-A6x25’s superior airflow and pressure performance. 
AAO Frame.
Noctua’s AAO (Advanced Acoustic Optimisation) 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 Design.
Noctua’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.
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 Pads.
Integrated Anti-Vibration Pads made from extra-soft silicone minimise the transmission of minute vibrations while maintaining full compatibility with all standard mounting systems and fan clips used on heatsinks. 
Smooth Commutation Drive 2.
The latest version of Noctua’s advanced Smooth Commutation Drive system ensures superb running smoothness by eliminating torque variations and switching noises. This makes the NF-A6x25 remarkably quiet even at very close distance.
SSO2 Bearing.
The NF-A6x25 features the further optimised 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 stabilisation, precision and durability.
3 speed settings for full flexibility.
Providing 3000, 2400 and 1600 rpm speed settings via the supplied Low-Noise and Ultra-Low-Noise Adapters, the NF-A6x25 FLX (Flexibility) can be fine-tuned for superior airflow or maximum quietness.
Extensive Cabling Options.
The fan’s short 20cm primary cable minimises cable clutter in typical applications while the supplied 30cm extension provides extended reach when necessary. Both cables are fully sleeved and the supplied 3:4 pin adaptor allows to connect the fan directly to the power supply.
6 years manufacturer’s warranty.
Noctua fans are renowned for their impeccable quality and outstanding longevity. Like all Noctua fans, the NF-A6x25 features an MTBF of more than 150.000 hours rating and comes with a full 6 years manufacturer’s warranty.