AAO Frame
Anti-Stall Knobs
Focused Flow™ Frame
Inner Surface Microstructures
Sterrox® liquid-crystal polymer (LCP)
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.

More information: Stepped Inlet Design
Inner Surface Microstructures