neverest RK 4" Professional Backdraft Shutter Damper Connector Duct

Key features

• ✅ WELL-MADE The 4 inch backdraft damper is made out of a galvanized steel while the flap leaves are made of aluminum. The axis and spring are made of stainless steel, 3.5 inches deep, and can withstand temperatures from 14 to 140 °F. The backflow damper prevents the ingress of cold or warm air and wind from entering through the ventilation duct.
• ✅ FEATURES 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.
• ✅ MULTIPLE USE Designed for use in air conditioners (AC), dryers, exhaust, extractor or range hoods, heating ducts, vents, and other HVAC applications.
• ✅ EASY 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.
• ✅ NOTE 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.