be quiet! Silent Wings Pro 4 - 140mm 2400 RPM

Optimized fan blades for the highest performance on radiators and heat sinks. Speed switch allows changing maximum PWM speed between medium-speed, high-speed and ultra-high-speed (up to 2400 rpm). Small tip clearance and a fan frame with a funnel-shaped air outlet for extremely high air pressure. Virtually inaudible operation at regular speed. 6-pole fan motor and fluid-dynamic bearing for less vibration and very smooth operations