The Vents KOM 125 U Spring-Loaded Backdraft Damper is made for 5" round duct systems. It prevents backdraft, insects, and birds when the ventilation system is off. Its operation is simple: blades open with airflow and close securely due to a strong spring. This KOM 125 U damper is easy to install in 5" round ducts, and features a 26 gauge galvanized steel housing and precision-engineered aluminum blades with spring action. It also has foamed rubber seals for noise reduction and airtightness. Perfect Solution for Bathrooms, Cottages, Kitchens, Apartments and Tiny Homes. What makes a Vents Backdraft damper special? Read our Blog here. Need larger quantities?We work with contractors, developers, and builders across North America. Call us toll-free or email our sales team - we’ll get you great pricing for your project. Features: 26 gauge Galvanized Steel construction Compatible with a 5" duct Spring Loaded Damper Rubber Seal