2 Pcs 4 Inch Draft Blocker Backdraft Damper Duct Draft Stopper OneWay Airflow Ducting Insert Backflow Preventer Inline Fan Vent Deflector

Product ContainPackage includes two backdraft damper with diameter of 4 inch 100mm Please confirm the size before purchase All dimensions are measured manually please allow 13mm differences Quality MaterialThe 4 inch backdraft damper is made of a Galvanized steel the flap leaves are made of aluminum InstallationThe backdraft damper is installed by pushing it into the ventilation pipe as far as it will go The position of the spring should be horizontal when the flap is installed horizontally so that it can be opened and closed optimally This also applies to the vertical installation FunctionThis airflow regulating backdraft shutter fits over the TD lip and is designed to improve ventilation by preventing air from recirculating when the fans are not in use Back draught valves can be inserted into ventilation ducts which are flexible or non flexible Cannot be used with plastic ducts as the sizes are different Wide Application These backdraft dampers can be widely used in ACs exhaust fans extractors range hoods heating ducts vents and other residential commercial and industrial applications