The NF-A9 is a highly optimized, quiet 92mm high-quality fan. With Noctua's AAO (Advanced Acoustic Optimisation) frame and refined aerodynamic design featuring Flow Acceleration Channels, the NF-A9 further enhances the renowned quiet performance of the award-winning NF-B9. The PWM version incorporates Noctua's specially designed NE-FD1 IC for fully automated speed control via a 4-pin connection and includes the Low-Noise-Adaptor to reduce the maximum speed during PWM control from 2000 to 1550 rpm. The exceptionally smooth operation, SSO2 bearing, and Noctua's reliable superior quality make the fan a top choice for the highest demands.