Regulates the flow of air in a HVAC system, up to 2,000 FPM, and low differential pressure, up to 1.0 in. w.g. Offers the ability to control damper remotely (using No. 48C165) by connecting to the wall/ceiling plate or diffuser. Round remote powered balancing dampers are ideal for applications where it is difficult to get access to manually adjust the dampers and balance the airflow. 20-ga single blade, balancing dampers are for installation in any position with the blades horizontal. There is no top or bottom. Design incorporates 20-ga galvanized steel construction for durability and longevity.