Vent Systems 6'' Inch Backdraft Damper - Backflow Shutter - Heavy-Duty Inline Springs Loaded - One-Way Airflow Ducting Insert - Inline Fan Vent Deflector

Excellent product!!! Opens when it's supposed to, and closes when it's supposed to. I have tried the "Fantech" brand, but it ends up binding after awhile, due to poor quality axle assembly and a weak spring mechanism. This Vent Systems damper utilizes a double spring and larger diameter axle rod. Flanges are also more heavy duty, with rubber seal along flange resting area. Overall a much better product!! Thanks Vent Systems!!

Installed for my range hood. Put this up near the termination through the roof, works well and hardly makes any sound when it opens or closes. Make sure when you install this that you're not putting it right next to the fan if you can avoid it. Putting it further down the line will help with static pressure and airflow.

Worked perfect for microwave hood exhaust.

After ordering in the winter, I finally got a hold of the roofer to pull the old exhaust on roof so I could replace it and add this damper in the trunk line.Installed just after the kitchen exhaust comes up through the ceiling cavity. Keeps the conditioned air out of the attic and closer to where it needs to be to prevent condensation dripping back.Installed easily. However, like other reviews say, the springs are strong.... maybe too strong. I installed it vertically in a 6" round duct that goes straight up.For now I can only use the kitchen exhaust on High Speed mode. Low setting will not allow the damper flaps to budge.Foam gasket does help eliminate the slamming metal sound you normally would get.

Works great! Keeps the wind out of my stove pipe to my wood heater.

To small.

Works great and well made

Very good quality bought, the shaft on the center comes out quite a bit and was very hard to get it in the 6" duct. You will have to make it work and will not be easy.