The NF-A15 is a premium quality quiet 140mm fan with a round frame that complies with Noctua's AAO (Advanced Acoustic Optimisation) standard. The NF-A15's frame features 120mm mounting holes (105mm spacing) and has been enlarged to 150mm width in order to provide superior performance on today's high-end CPU coolers. Featuring sophisticated aerodynamic design measures such as Flow Acceleration Channels, the NF-A15 further improves the renowned quiet cooling performance of the award-winning NF-P14. Noctua's custom designed PWM IC for fully automatic speed control and reference class SSO2 bearings guarantee superb running smoothness and excellent long-term stability. Topped off with modular cabling, a Low-Noise Adaptor and 6 years manufacturer's warranty, the NF-A15 is a premium choice for the highest demands.