Bgears 90 mm 2 Ball Bearing High Speed High Performance Fan, Translucent Black (b-PWM 90 Black 2ball) Speed range from 500 to 4000 RPM with Excellent Airflow of up to 88 CFM 9 translucent Black blades design for ultimate airflow and low noise level at only 39dBA PWM Technology with mini 4 pin 4 wire connector to connect directly to the Motherboard fan connector for ultimate fan speed monitoring 2 ball bearing designed for high speed and high performance Include a 3 to 4 pin Molex adapter for direct connection to Power Supply.