The NF-A14 is a premium quality quiet 140mm fan with a square frame that complies with Noctua's AAO (Advanced Acoustic Optimisation) standard. Its square shape and 140mm mounting holes (124.5mm spacing) make it ideal for use on watercooling radiators or as an upgrade for 140mm case fans. Featuring sophisticated aerodynamic design measures such as Flow Acceleration Channels, the NF-A14 further improves the renowned quiet cooling performance of the award-winning NF-P14. The PWM version sports Noctua's custom designed NE-FD1 IC for fully automatic speed control via 4-pin fan headers and comes with a Low-Noise-Adaptor to reduce the maximum speed during PWM control from 1500rpm to 1200rpm. Its performance-oriented 1500rpm top speed and comprehensive speed control options make the NF-A14 PWM an elite choice for users who strive to strike a perfect balance between excellent cooling capacity and superb quietness of operation, be it on watercooling radiators, on heatsinks or in case ventilation.