Noctua Premium Fan, Brown, NF-A4X10-FLX 5V Award-winning 40x10mm A-series fan with Flow Acceleration Channels and Advanced Acoustic Optimisation frame for superior quiet cooling performance Ideal replacement for noisy or broken 5V 4cm fans in 3D printers, DVRs, NAS, switches, routers, other network and storage devices, etc. 3-pin 5V version with 4500rpm, not to be used at 12V (such as in PC environments) Includes anti-vibration mounts, fan screws, Low-Noise Adaptor, extension cable and OmniJoin adaptor set for connecting the fan to proprietary fan headers Trusted Noctua quality with premium-grade SSO2 bearing and more than 150.000 hours MTTF, backed up with 6-year manufacturer-warranty