The be quiet! Silent Wings 4 140mm PWM High-Speed White (BL117) is a premium high-performance PC cooling fan designed for gaming PCs, enthusiast systems, workstations and custom PC builds. Combining strong airflow, high static pressure, advanced bearing technology and a clean white finish, the Silent Wings 4 BL117 is suitable for use as a case fan as well as for demanding radiator and heatsink applications.