4 Inch Backdraft Damper Back Draft Vent Duct Shutter Blocker, Backflow Ducting Insert One-Way Airflow Preventer with Inline Springs Loaded Folding Blades, HVAC Extractor Range Fan Hood Deflector

Just what I needed to retrofit into my Stove vent hood duct

With basic knowledge, I was able to install in less than 10 minutes. It prevents the backdraft that was present before the installation!

Arrived within a few days. Good quality. I used it to prevent backdraft in a dryer vent. The air from the adjacent bathroom fan no longer goes into the dryer.

Working very well for the price. I would recommend

This is a good quality, well built dampener. It uses a high density foam weatherstrip on the back for the wings to rest against. This helps seal it up nicely when not in use. This is FAR better than the typical Chinese junk you see. Very happy and will recommend to all.

This is a good damper part and is better than nothing, but the springs are fragile, and the damper wings are incredibly flimsy. The central bar holding the wings is also very weak and was already bent on delivery. Reasonable value for the money but not for higher end installations.

Amazingly good seal on damper. Using in dryer vent and no more cold air Inleakage. Minimal pressure required to open so does not obstruct air flow.

WELL MADE NOT ,,, DOES THE JOB,, I WOULD INSTALL THE UNIT.. WITH SWING BAR.... VERTICLE JUST IN CASE THE SPRINGS ,,, EVER BREAK OR EVEN U DO GET.... A OUTSIDE BACK DRAFT,, THE BREEZ WILL SHUT THE UNIT WINGS... AGAINST THE BACK STOP...

I installed it as make up air intake. In theory should demand become nessary, it should open by demand and close when nessary.

sa vas très bien

The vent spring requires significant air flow to open. A fryer is fine but my range hood could not. The foam seal on the inside of unit provides an excellent backdoor preventer.