Noctua NF-A4x20 FLX Computer Case Fan - Cooling Components - Computer Case, Fan, 4 cm, 3700 RPM, 5000 RPM, 4400 RPM. The FLX version provides 5000/4400/3700rpm speed settings via the supplied Low-Noise Adaptors and includes the OmniJoin Adaptor Set for easy connection to proprietary fan headers.
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