The NF-A15 is a premium quality quiet 140mm fan with a round frame that complies with Noctua ?€° ?› ?ªs AAO (Advanced Acoustic Optimisation) standard. The NF-A15 ?€° ?› ?ªs frame features 120mm mounting holes (105mm spacing) and has been enlarged to 150mm width in order to provide superior performance on today ?€° ?› ?ªs high-end CPU coolers.