The NF-A4x10 is a highly optimized, quiet 40x10 mm fan of premium quality, utilizing cutting-edge aerodynamic design features such as Flow Acceleration Channels and Noctua's AAO frame system. The PWM version employs Noctua's specially designed NE-FD1 IC for fully automatic speed control via 4-pin connectors and comes with a low-noise adapter as well as an OmniJoin adapter set for operation with proprietary connectors. Its exceptional smoothness, the SSO2 reference-class bearing, and Noctua's proven premium quality make the NF-A4x10 PWM an exquisite choice for the highest demands.