High Airflow 148CFM: 120x120x38mm high speed dual ball bearing PC computer fan with 3500RPM 148cfm,designed for those who need very strong airflow cooling fan. Specification: Fan Size: 120x120x38mm 4.72x4.72x1.5inch Speed: 3500 RPM±10% Airflow: 147.93CFM Noise: Max 51dBA Current: 0.5A±10% Power: 5.5 W±10% Interface: D type 4Pin Air Pressure: 21.8mm H2O. D Type 4Pin Interface: Multiple fans can be directly connected to the power supply cable in series with D type 4pin connector, solving the problem of insufficient motherboard interface. 51dBA Noise: This is not quiet case fan,noise level is around 51dBA like persons conversation. Wide Application: The fans can be used for router, amplifier, cabinet, greenhouse, fish tank, dog kennels, plant sheds ventilation and other DIY cooling projects.