neverest RK 4" Professional Backdraft Shutter Damper Connector Duct
 
Product Features
  

         
The backflow damper prevents the ingress of cold or warm air and wind from entering through the ventilation duct. 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, 3.5 inches deep and can withstand temperatures from 14 to 140 F
         
Designed for use in air conditioners (AC), dryers, exhaust, extractor or range hoods, heating ducts, vents and other HVAC applications
         
The backflow flap opens and closes automatically at low air volumes. It has a smooth-running spring and an internal foam strip to keep the blades from rattling and can be installed horizontally or vertically
         
INSTALLATION: The backflow flap is installed by inserting it into the ventilation pipe until it stops. The position of the spring should be horizontal for horizontal installations so that it can open and close optimally. The Backdraft shutter is installed so that the damper blades open only in the outflowing air direction.
         
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.