The DiversiTech 625-AF10 Duct Fan is a high-capacity inline duct booster fan engineered to improve airflow, balance temperatures, and increase HVAC system efficiency in residential and commercial applications. With a powerful airflow rating of up to 650CFM and a durable 10-inch metal housing, this fan is ideal for boosting airflow in long duct runs, large rooms, additions, basements, and other hard-to-condition spaces.