PATIKIL 8" HVAC Duct Manual Volume Damper, Metal Adjustment Airflow Ducting Backdraft Damper Control for Air Ventilation System

This assembly is made with relatively heavy tubing. The damper has polymer edge seals, so it can close almost hermetically. The damper blade bearings are superior to those in usual duct dampers. The damper handle is made of stamped sheet metal with sharp edges, so it is advisable to wrap it with duct tape or similar.A potential difficulty is that the diameter of both ends is somewhat smaller than U.S. standard 8". It will fit snugly inside the crimped male end of U.S. duct, but it will have a significant gap inside the plain female end of U.S. duct. Shoving the raised collar of the damper assembly into the female end of the duct reduces the gap. Screws and duct tape should be used at both ends.

I don't like dampers in general. Usually they are flimsy and require maintenance and adjustment. These, on the other hand, are fantastic. They seal extremely well. They are very solid. The adjustment mechanism is exactly what you'd want.

Easy to install and use. Very sharp edges, so use gloves to install product. Damper label is not in English for a product sold in U.S. on Amazon, the reason why it's a 4 Star product.

This is a well built damper with a solid handle/damper mechanism and thick walled pipe. One caution is that the diameter seemed a tiny bit small for a US standard 4" pipe, but the fit was still adequate. It sealed well with some good tape. I speculate that it may be built to a 100mm size, which is pretty close to, but just a bit smaller than 4".

Damper is made of thicker gauge metal so does not flex. Damper seals extremely well so basically no air passes when closed. Would highly recommend.

I needed to balance out the air flow within my home, half the house gets strong air, the other half, not so much. These worked amazing to minimize the air flow on the ducts that got more air so it can then flow through to the remainder of the house. Great quality, would recommend strongly if you have the same problem!

It does what it is supposed to do. It seals the air very well. If you know what you're doing then the installation is pretty easy. Yes it's slightly under 6" but you want that so flexible duct can fit over the ends. If you aren't connecting to flexible duct, you could probably bend the ends to fit into wherever you want it, or just buy a few feet of flexible duct and make it work.

The plastic seal on the valve plate really does seal off air flow. No leak air slipping past it or hearing a whistling sound because of air leakage. Great fit.

Solid and well built and still 5 stars even with the following design issue.Its a real beauty honestly.It does fit small as others have said, about 1/4”, so you have to “lightly” crimp the ducts connecting to it(pre-crimped ends won’t work as they will line up exactly with damper edge)And while you use crimped ends, the damper however fits INSIDE the crimped ends unlike a regular crimp connection. See photo

I wanted to install a damper on a 6 inch heating duct and this product worked perfectly.

It's good