Noctua NF-B9 PWM Cooling Fan<div style="text-align: left;"><strong>[Product Information]</strong><ul><li id="replacementPartsFitmentBullet" class="aok-hidden" data-doesntfitmessage="We're not sure this item fits your " data-fitsmessage="This fits your "><span class="a-list-item"><span id="replacementPartsFitmentBulletInner"><a href="#" class="a-link-normal hsx-rpp-fitment-focus">Enter your model number</a>to make sure this fits.</span></span></li><li><span class="a-list-item"> Beveled blade tips reduce critical rotor/ stator interaction， combine a higher blade surface area with quieter operation and form a cornerstone of the fan's efficiency. </span></li><li><span class="a-list-item"> Vortex-control notches split up trailing edge vortices and spread the fan's noise emission over a wider range of frequencies. </span></li><li><span class="a-list-item"> Supporting fully automatic speed control， the NF-B9 uses Noctua's novel， custom-designed NE-FD1 IC that integrates Smooth Commutation Drive (SCD) technology. </span></li><li><span class="a-list-item"> The NF-B9 PWM is supplied with a Low-Noise Adaptor (L.N.A.) that reduces the maximum fan speed from 1600 to 1300rpm. The L.N.A can run the fan at a fixed speed of 1300rpm or cap the maximum speed when using automatic control. </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/51ODVx8do7L.jpg" noproxy>