Bgears b-Blaster 140 x 38 mm Black (PWM Version) 2 ball bearing high speed high performance fan. Extreme Speed at 5200 RPM with Excellent Airflow of up to 308 CFM. 38mm thickness Frame design for large motor to generate ultimate speed and airflow. Mini 4 pin 4 wires connector with fan speed signal output. Include 4 mounting screws.