【Material】The 4 inch 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.
【Installation method】The position of the spring should be horizontal for horizontal installations so that it can open and close optimally
【Wide applications】Back draught valves can be inserted into ventilation ducts which are flexible or non-flexible. Designed for use with range hoods, bathroom fans, kitchen and other home HVAC applications.
【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.
【Backdraft Shutter】Hon&Guan Draft Blocker designed to improve ventilation by preventing air from re-circulating when the fans are not in use, rubber ring ensure 100% closure and quiet closing.