Noctua's S12A 120mm fans is the 3rd generation Signature series line designed for case ventilation. The Noctua S12A is available in three versions: PWM, FLX and ULN. Both the FLX and PWM versions run at a maximum of 1200 RPM with an airflow rating of 107.5 m3/h while the ULN version runs at a lower 800 RPM with an airflow rating of 74.3 m3/h. Unlike the 2nd generation S12 series fan, the new S12A series are equipped with anti-stall knobs that reduce flow separation in medium to high impedance situations, increasing the fan’s versatility. Also part of Noctua’s Advanced Acoustical Optimization design are the inner surface microstructures as well as the stepped inlet design which improves airflow and minimizes noise during operation. All three Noctua S12A 120mm fans use Noctua's SSO2 bearings with a MTBF of 150,000 hours and carry a 6-year warranty.