YOUNTHYE 4 Inch Backdraft Damper, 2PCS Inline Springs Loaded Backflow Preventer Backflow Shutter, One-Way Airflow Ducting Insert for 4”Ducting in Range Hoods and Bathrooms Fans

• UPC   696629987305
• Size of Backdraft Damper - 4 inch/ 100mm in diameter, 3.5inch/ 88mm in length, 0.5MM/0.02 inch in thickness, 2 in package. Please confirm the size before purchase. Durable & Premium - 4 backdraft damper is made of galvanized steel and the dryer vent valve flaps are made of aluminium the butterfly damper axis and spring are made of stainless steel. Preventing Unwanted Drafts - 4 inch backdraft damper opens and closes automatically to prevent backflow and debris from entering ducting. Application Scenarios - 4 backdraft damper fit for 4" Duct Openings. Backdraft damper 4 inch designed for use with range hoods, bathroom fans and other home HVAC applications. Not for use in plastic ducts. Easy to Installation - The 4 inch 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.