The NF-A14 is a premium quality quiet 140 mm fan with a square frame that complies with Noctua's AAO (Advanced Acoustic Optimization) standard. Its square shape and 140 mm mounting holes make it ideal for use on water-cooling radiators or as an upgrade for 140 mm 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 1500 rpm to 1200 rpm. Its performance-oriented 1500 rpm 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 water-cooling radiators, on heatsinks or in case ventilation.