PATIKIL 4-Inch Backdraft Damper Stainless Steel Flexible Airflow Ducting Insert Backflow Preventer Draft Blocker for Kitchen Bathroom Exhaust Fan Silver

The backdraft damper prevents fumes, exhaust, debris, dust, and odors from entering your room when the ventilation fan is off, and is widely used in dryers, range hoods, and HVAC systems in homes, kitchens, bathrooms, and offices.

Made of durable 201 stainless steel, it is rust-proof, scratch-resistant, corrosion-resistant, moisture-proof, and easy to clean for long-term use.

When exhaust starts, air pressure opens the valve; after exhaust stops, the damper automatically closes to keep indoor air fresh.

To install, fix the damper to the vent hole with spring clips, apply sealing glue around the base, and attach the vent hose with pipe clamps.

Please confirm the outer diameter before ordering, and note that sealing glue is not included.