Hon&Guan 4 Inch Backdraft Damper Kit-16ft

Upgrade design The 4 inch damper on both sides of the top and bottom of the two new concave inward pressure rib, and increase the thickness to 0.6mm,to ensure that the product is more solid, not easy to damage., Material The backdraft damper and the flap leaves is made of a galvanized steel, the axis are made of aluminum, while the spring are made of carbon steel., Lightweight valve wings The valve wings open under the pressure created by the airflow; when the air flows in the opposite direction, it is automatically closed under the action of the spring, so as to cut off the flow. Rubber ring ensure 100% closure and quiet closing.,Low Noise Silencer: Designed for reducing noise from fans and carbon filter systems, can decrease the noise by up to 50%,3-Layer Tough: Keep your ventilation system free of rips and pin holes. Under the Black PVC layer our ducting is built with 2 layers of Aluminum Foil With a layer of PET and Steel Wire Helix to preserve the shape,keep your ventilation system free of rips and pin holes