4 Inch Draft Blocker Backdraft Damper Duct Draft Stopper One-Way Airflow Ducting Insert Backflow Preventer Inline Fan Vent

pretty light weight but I think that's by design. Alum so no rust worries - very light spring action. Fit perfectly in the existing duct work. I wasn't able to use the baffle on the fan I bought for the bathroom so this was a nice alternative. Read more

Perfect for my installation. Too many of these type dampers have very stiff springs and it will not work with low CFM air flows. These are great. You can blow at them with your mouth and get them to open. And they seal very well. I use them for air circulation between rooms with fans set to about 60 CFM. The last ones I got restricted about 80% of the air. These only restrict maybe 10%. This is key for low CFM situations like bath exhaust fans, for instance. Read more

This draft blocker worked perfect. I was concerned it wouldn't fit inside my old pipe and yet have my old elbow Go over it. It works great to prevent the cold air from going down my dryer vent. I was having trouble with condensation developing on the vent and leaking on the floor. This solve that problem I would recommend it for anybody. Read more

Pretty good. It stopped the bad backdraft I had, but the center hinge has a bit more gap than I'd like. Read more

I read the lower than 3 star reviews before I purchased and I purchased anyway. Of course there was no instructions but I’m familiar with these things. This damper needs to be installed in the correct orientation. Hinged doors open to the outside. It needs to be connected to the existing 4” exhaust pipe with foil tape (ensure no leakage) on both sides with the spring hinge in a horizontal or vertical position. If you follow those simple rules this thing works great! My 50 CFM fan moved air with no issues and there is no air from the windy outside pushing back into the house. I would say that the closer you install this damper to the outside damper that is attached to your house, the better your results. I would buy this again. Correct installation is everything. Read more

Each time the A/C or furnace kicked on it would draw outside air in through the vent hood. Cold in the winter and hot in the summer. The temperature under the hood was significant and very noticeable. So I installed this draft blocker in the pipe in the attic, separating the pipe at a joint inserting the valve and reconnecting the pipes. I seal the joints with aluminum tape. The draft blocker has a weather strip inside sealing it when not in use. I did have to reseal the pipe where it passed through the roof with roof tar to restore the water seal. It works great, the is no back draft now when the A/C is running and made a huge difference. I would recommend and buy again. Read more

Great price Great product Read more

These work great for what I need them for. They open and close a few times a day and have been working that way for about seven months now. Simple to install not much else to say. Read more