【Size Specifications】Designed for 8 inch (203.2mm) ductwork, the damper has a straight-end diameter of 8 inches and a bent-end diameter of 7-7/8 inch (200mm), with a total height of around 6 inches (152.4mm). 【Durable Galvanized Steel Build】Crafted from premium galvanized steel, this damper offers exceptional hardness, heat resistance, and extended service life. The zinc coating provides reliable protection against rust and color degradation. 【Precision Airflow Regulation】Equipped with a calibrated control scale and multi-position handle for precise airflow adjustment. For optimal performance, install with the handle in an accessible position to maintain climate control efficiency and effectively block reverse airflow. 【Easy to Install】Designed for effortless setup - simply insert into standard ductwork and secure it with pipe clamps or tape. Requires no special tools or expertise, suitable for both professional contractors and DIY installation. 【Universal HVAC Compatibility】Engineered for precise airflow control in various HVAC systems, ducts, and ventilation networks. Suitable for air conditioning, dryer exhausts, range hoods, heating, fans, and more—serving homes, businesses, and industrial facilities.