SILENT WINGS 4 140mm PWM NO COMPROMISE SILENCE AND PERFORMANCE Silent Wings 4 140mm PWM combines all features of a virtually inaudible with an extremely performant fan for the most demanding applications. Optimized fan blades for the highest performance on heat sinks Small tip clearance and a fan frame with funnel-shaped air outlets 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 Anti-vibration mounting with push pins and screwed installation option Super-long lifespan of up to 300,000h Elegant look with high-grade fan sticker in an all-black design