Massive 180 mm blades yield remarkable airflow while staying quiet High-grade LLS (Long Life Sleeve) bearing with 90,000-hour MTTF PWM support offers a wide 300 to 1200 RPM speed adjustment range Aerodynamic stator struts reduce noise and turbulence Blade edges with strategically placed notches eliminate fan hum Trip Wire technology increases blade efficiency and decreases noise Sound Level: 16 - 35.4 dBA Airflow: 44.9 - 153.7 CFM