Balancing dampers are simply manual dampers encased in a galvanized sheet metal sleeve. Each branch should have a balancing damper installed. That way, it's possible to regulate the airflow by adjusting the position of the damper. They should be located in areas that are easily accessible for adjustment. Typical uses are for rooms that get minimal use and can be closed off for extended periods of time or rooms that need different amounts of air flow in the summer and winter. Our Damper & Sleeves are made from Galvanized Steel and Duro-Dyne RS256 Jiffy hardware. Sleeves are diameter plus 2 inches for overall length.