The Vents US KOM 100 U Spring-Loaded Backdraft Damper is designed for round duct systems. This essential component ensures the prevention of backdraft (and insects, birds, etc) when the ventilation system is inactive. Its operation is intuitive – the blades automatically open when air flows through, and they securely close thanks to a robust spring mechanism. Designed for easy installation, this high quality damper is seamlessly integrated into round air ducts and secured in place with clamps. Crafted from high-quality galvanized steel housing, it features precision-engineered aluminium blades with spring-loaded action. To enhance performance and reduce noise, the damper is equipped with foamed rubber seals that provide both noise absorption and exceptional air tightness. 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: 24/26 gauge Galvanized Steel construction Compatible with a 4" duct Spring Loaded Damper Rubber Seal