An air duct damper is a device used to control the flow of air in an HVAC system. It is typically installed in the ductwork of a home or building and is used to regulate the amount of air that flows through the ducts. The damper can be opened or closed depending on the desired amount of air flow. This is done by either manually adjusting the damper or by using a motorized actuator. The damper is an important component of an HVAC system as it helps to regulate the temperature of the air and can help to improve energy efficiency. It also helps to reduce noise levels and can be used to help balance the air flow in different areas of the home or building.