PROCOOL SP640X-E / 1U Temperature Controlled Silent Rack Fan/Airflow= EXHAUST/Home Theater AV Cabinet Cooling Broadcast Server Recording Studio Rack Fan 1U 1 rack space / 19" x 1.75" x 2" / Airflow= EXHAUST at 36 CFM - Noise= 21 dBA Silent fans / Best for any application where silent cooling is required. Good airflow with literally no noise. The fan controller monitors temp and starts and stops the system at user defined set point. Select from Intake or Exhaust. Fans can be easily flipped over to change airflow if needed. 2 Year Warranty - Built by hand in the USA