In Duct Non-return (backdraft) Dampers

Non-return dampers have traditionally been installed between two lengths of duct, rather like a coupler: new in duct dampers can be inserted directly, simplifying installation.

Lightweight aluminium blades on a light steel spring maintain the damper in the closed position when no air is flowing, preventing wind/drafts from flowing back through the duct. These dampers feature seals and rolled edges.