2 Pcs 6 Inch Draft Blocker Backdraft Damper Duct Draft Stopper One-Way Airflow Ducting Insert Backflow Preventer Inline Fan Vent Deflector

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.

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.

nice ,it works.

Works well, makes a tight seal, no tapping sound when the flaps close, a little undersized for 8 in hvac. But not so much that some hvac tape couldn't seal it. Easy to install. Seems like it will hold up for a long time. Decent damper for the price.

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.

Fits and work well.

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.

If this vent is installed with the air flow going down, the springs will be challenged to close the vent due to the weight of the fins. Likewise if the orientation is horizontal with the hinge flap horizontal, the spring will struggle. The construction and fit is solid with a good seal when closed. Will do the job keeping in mind these conditions.

it works very well...no more cold air in my kitchen.

works great, as advertised

Excellent design, construction, and workmanship. The shell is made of rigid sheet metal and the butterfly dampers of aluminum. The dampers are normally held in the closed position against the seal by light springs. The dampers open in one direction by just blowing against it. Both ends of the shell fit perfectly inside 4 inch diameter ducting. The plain ends allow it to be easily installed in an existing ducting that needs a backflow preventer. It even had a sticker noting how to orient the dampers properly when installing it horizontally. I used it to prevent wet exhaust from our clothes drier backflowing to our washroom. Both drier exhaust and washroom vent were tied to a tee that exhaust to the outside. Our washroom vent fan damper was not enough to keep moist air from our drier from backflowing into our washroom.

I used this to keep the cold from coming into the house throught the dryer vent. It works great, and was easy to install. It has a foam seal instead of the hard rubber ring that another one I purchased on Amazon at almost double the price had (I returned that one because I could see daylight between the flaps and the rubber "gasket"). I deducted a point because the foam seal was not installed accurately, but Iwas able to adjust it fairly easily. The manufacturer need to take more care assembling these, as the whole point is to not have cold air leak padt it.

I used this in my kitchen range exhaust, which already had a flap in the portion outside the house but still let in a lot of cold air. I installed it immediately after the outside vent and this almost completely stopped the cold air coming in above the range. Some small amount of air still comes in around the hinges in the middle.