The Pure Wings 2 family fans are unique in itheir class combining outstanding reliability silent cooling and a great price-for-performance ratio. It's impressive how much quiet technology the German engineering team has crammed into these fans at this amazing price. They are the ultimate reason to put well-known be quiet! silent cooling in your PC if you haven't already done so. Practically Silent Operation Up to nine silence-optimized fan blades with high airflow capabilities reduce noise-generating turbulences while increasing air . pressure.   . Very quiet operation even at maximum speed with noise of max. 20.2dB(. A.  ) . Variable Speed Function . Pulse Width Modulation (PWM) allows compatible 4-pin controllers (including those built into many motherboards) to intelligently vary the speed (and thus the noise level) of the fan . With PWM your system can ramp up the cooling when it's needed or operate in maximum quiet mode when it's not Product conception design and quality control in Germany Perfect choice for home and office PCs gaming and multimedia systems . Especially recommended for use in water cooling and CPU cooling builds . High-quality rifle bearing technology contributes to a very long lifespan of up to 80000 hours . 3-year manufacturer's warranty .  .