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

I was worried this would be restrictive to my air flow but it's hardly noticeable. It opens easily. Working great venting my grow tent outside. It blocks all air and bugs from getting in.

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!

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

It was great. You will have to seal it when connects to your duct fan, but that's for all products no matter what. The quality of the material is great

The flaps would rub against the bottom of the damper. I wrapped a paper clip around the bottom part of the rod to make a washer and cut off the excess. This raised the flaps high enough so they no longer rubbed. The damper must be installed with the flaps oriented vertically (like a door). When connecting the damper to the duct work, the crimped end off the existing duct will not fit into the damper so the crimp needs to be cut off and the damper will slide into the duct. When installing a sheet metal screw, there's no issue on the supply side but on the exhaust side the screw must be either at top dead center or bottom dead center so it will not interfere with the flaps opening. Once installed, the damper worked great and stopped the cold outside air from entering the stove exhaust.