be quiet! SILENT WINGS PRO 4 | 140mm PWM, Fan, 5.51" (14 cm), 2400 RPM, 165.5 m³/h, Black be quiet! SILENT WINGS PRO 4 | 140mm PWM. Type: Fan, Fan diameter: 5.51" (14 cm), Rotational speed (max): 2400 RPM, Airflow: 165.5 m³/h, Maximum air pressure: 3.64 mmH2O, Bearing type: Fluid Dynamic Bearing (FDB). Voltage: 7 - 13.2 V. Width: 5.51" (140 mm), Depth: 5.51" (140 mm), Height: 0.984" (25 mm). Product color: Black https://www.techpowerup.com/review/be-quiet-silent-wings-pro-4-120-mm-pwm-fan/ be quiet! recently celebrated its 20th anniversary with a slew of new product releases including the Pure Base 500 FX case as well as the Pure Loop 2 FX 280 AIO cooler. Add in the recently released Pure Rock 2 FX cooler and the Light Wings 120 and 140 mm... Excellent balance of performance and noise, Silence-first for those wanting a quiet PC, Three operating modes allow flexibility in operation, Linear RPM, noise, and airflow profiles, Minimal sample variation, No bearing noise in use, Fairly efficient moto... Quite expensive per fan, no multi-fan discounted SKU available here, Some impractical accessories drive up the cost The be quiet! Silent Wings Pro 120 mm PWM fans cost $30.90/€31.90/£28.99 from authorized retailers listed here as of the date of this review. Excellent balance of performance and noise Silence-first for those wanting a quiet PC Three operating modes allo...