Panasonic BDD-8 Atmosphere Backdraft Damper 8-inch, Spring Loaded; For Models VTX800; VTX800LPanasonic BDD 8 BDD 8 Product Description Atmosphere backdraft dampers are manufactured with galvanized steel and can be mounted directly in the ventilation duct to ease the installation. The two blades have an independent hinge to prevent any malfunction. The dampers come with a gasket to ensure a quiet and sealed operation. Features: For use with Atmosphere Vortex Series In line fans and Atmosphere Dryer Exhaust Duct Power Ventilators Neoprene