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

Reduces backflow and they work perfectly. Good product at a great price.

Put a fan in my garage and need a damper. This one is nice had a good seal and the spring opens and closes easily.

No problems installing, and works as advertised.

This worked perfect. One end went inside the vent pipe to the outside and the other side went into the flex hose inline with the vent. Took longer to pry up the attic boards than to install this. It stopped that popping noise from the vent fan in the wind. The metal on this is very thin and I can see how some got damaged in shipment. That being said it does work very well. Make sure you use that tape that seals the seam in duct work and to not struggle with the clamps use a clamp that is for 4-6 inch or 4-5 inch it depends on who made it, that way you do not struggle with putting the clamp on to secure everything. Hope this review helps. Steve

Nice light spring for a low CFM bathroom fan. Intergral sealing lip.

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.

I should have installed one of these backdraft blockers years ago! It was very easy to install and fit perfectly in my 10” range vent pipes. I’m looking forward to a more comfortable kitchen and lower energy bills in the winter months.

This fit and is what I wanted.

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 have allergies and apparently if I leave my portable Danby AC connected to the Window I wake up wheezing with Asthma or rather a type of bronchitis that fills my lungs with mucus from the allergies. Coughing and wheezing throughout the night. I had no idea that a backdraft damper existed or at least I could imagine that it existed but I had to search for "AC Duct air Blocker" to find that what I was looking for was a backdraft blocker. Measured twice the size of my Duct and it turns out that there are only three sizes 4", 6" and 8". My duct was 6.5". When my Draft Blocker arrived and I fitted it into the duct it was loosely fitted so I added a foam seal around the draft blocker and that made the backdraft blocker a tighter fit. Wasn't sure how far to push it into the duct but on the first try I decided to just have it near the entrance of the duct and that should be good enough. Checked that it was closed when my AC is not on and checked that I had Air flow when I turned on my AC by checking outside whether there was hot air blowing out of the exhaust. Yup works wonderfully. SOOOO theoretically without the outside air flowing through my AC duct I should have a good sleep tonight. I love how that if I have a problem such as a Backdraft on my AC Duct that I could find it on Amazon.

Damper fits over an existing 8" output. And has a foam gasket to make it quiet.

Did exactly what I purchased for it to do. Had a range hood with a broken damper and all you could feel was cold air coming in through the range hood. Installed it in the venting pipe and solved the problem instantly!! Saved myself $500.00 and alot of aggravation of changing out the whole unit.

Bought these to install in the air lines for our bathroom exhaust fans. The built in back draft flaps in the fans are awful so I wanted to get some improvement.Install was easy after making sure I bought the right size for our fan outlet and air line.The 110CFM fans I used these with have far more power than needed to force them open to exhaust the air. It didn't matter which way the flaps were positioned (horizontal or vertical) they opened with ease.Glad I went with this option!