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

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

Even with the regular dryer vent flaps closed the inside of my dryer would be cold when not in use. This solved that it simply slides over the vent pipe then vent hose attaches like normal pipe. Now it’s no longer cold inside the dryer and really makes a difference. It was a little out of round so I squeezed it lightly and it was good to go.

No problems installing, and works as advertised.

Works just as described

Completely stopped the drafts coming into my clothes dryer and causing a bunch of condensation. After I installed it on the line, I no longer have condensation!Wish I would’ve found this sooner.Keep in mind, you’ll likely need another 4” clamp.

The media could not be loaded.  I was looking for a backdraft preventer to keep out very cold air. The seal on this model is not tight, with almost a 1/4" gap between the backdraft wall and the flap, and also the flap and the foam seal. Not what I expected. Will get a better one.

This item has worked perfectly to keep the cold draft coming from the vent on my cooktop.

Needed to prevent backflow into my grow tent during the winter

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!

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.

No ussues, pretty good reverse flow prevention. Has a light spring to allow various mounting angles but careful not to deform while attaching hose or the flapper motion can he impeded. I used aluminum duct tape rather than hose clamps.

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.

It came in fast and was as described as a 4” oneway flow vent valve. I cut my 4” vent hose and this fit perfectly inside with no issues. I tightened two 4” clamps and it works perfectly.I would recommend this part