iPower 4 inch Shutter Back Draft Blocker, One-Way Airflow Ducting Insert Backflow Preventer with 2 Inline Springs Loaded Folding Blades, 4" Backdraft Damper, for HVAC Extractor Fan Vent, Range Hoods

iPower 4 inch Shutter Back Draft Blocker, One-Way Airflow Ducting Insert Backflow Preventer with 2 Inline Springs Loaded Folding Blades, 4" Backdraft Damper, for HVAC Extractor Fan Vent, Range Hoods

• Lightweight valve wings: The valve wings open under the pressure created by the airflow and then automatically close with the spring work. The backflow flap closes automatically at low air volumes. The Backdraft shutter is installed so that the damper blades open only in the outflowing air direction
• Keep away from rattling: It has an internal foam strip and a smooth-running spring to keep the valve wings from rattling. The position of the spring should be horizontal for horizontal installations so that it can open and close optimally
• One-way airflow ducting insert: Back-flow valve with 2 spring-loaded wings prevents the reverse airflow movement through the ventilation duct when the ventilation system is turned off
• Material: The 4 inch Backdraft damper is made out of a Galvanized steel, the flap leaves are made of aluminum, while the Axis and spring are made of stainless steel and can withstand temperatures from 14 to 140 °F
• 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. Essential for HVAC ventilation