Silent Wings Pro 4 PWM, 7 Blade, High Pressure Fan, 2400rpm, 97.41CFM, 36.8dB, Fluid Dynamic, 4-Pin PWM. Fans 140mm + be quiet! 140mm Silent Wings Pro 4 PWM Fan. For the highest performance, optimized fan blades, especially for heat sinks designed radiator corners and a speed switch with 3 selectable speed options, Silent Wings Pro 4 140mm PWM is the most progressive, performant, and versatile fan by be quiet!
