PATIKIL HVAC Duct Manual Volume Backdraft Damper, 4 Inch, Airflow Ducting Branch Vent Damper Air Control Valve, Adjustment Handle Stainless Steel, for HVAC

This is an excellent damper unit. When you order it, you should know that the housing is Stainless steel. This means that you will not be able to use regular sheet metal screws on it without cutting a hole first.I had to use a mechanical punch to cut holes in it. The stainless steel is nearly impossible to drill with a hand drill (you would need a drill press & lubrication jet to keep the drill from overheating).Once that problem was solved, it was installed easily and worked flawlessly. It is super sturdy and well-built because it is stainless steel. I am super happy with the unit.

Very well made strong , smooth operation and good baffle seal used for wood stove fresh air intake great price for the quality.

I am an HVAC Service\Installation Tech, this is an great product and very solid Stainless steel, you wont be able to use a self tapping screw or Comercial drill bit through this.. The Air seal is a 100% seal!!.. even by the holes....for for pipe sizing end specs:---the damper will fit nicely inside of a 6" round duct all the way to the Rib as long as it is not crimped on its end- it needs to be a flat raw end.I just used aluminum foil tape and taped it to the round duct, worked great---6inch duct flex fits perfectly over the damper end and zip tie it to securei used this for our fresh air intake for the house that goes to the return duct..-closed for summer to keep out the humidity-open during the winter to allow fresh air in to keep from getting stale air and refrain from getting a stuffy feeling

Well built. Worked good

Overall, I like the item it is a high quality material. I am a maintenance manager and know good material when I see it. I have been using it for two months so far have two different sizes

Nice HVAC valve. Stainless steel tough to drill even with high-end cobalt bits. Best to dimple, grind, then punch again to make a screw hole.

very well made. Can't believe it is this nice for such a low price.

I built my house a few years ago and have always had hot/cold spots and hot cold rooms, I hired an HVAC company to install the original furnace/AC system and they did an ok job but they never installed dampers and me being ignorant to this part I just chalked it up to not having the correct system? Talking to my neighbor we asked me if I had a damper system? No but I am thinking of putting in an automated one so I could adjust the rooms in the winter and summer to the families liking. He suggested just putting manual dampers in and the air balancing the house... I looked into it and before spending a fortune on the automatic system I thought I would give the manual units a try first. I bought many 4", 6", and a few 8" manual dampers and installed them in my flexible duct system with lots of tape and zip ties to seal for leaks, bought a BTMETER BT-100 from amazon and I can happily say I have a much more balanced house and I actually keep the temperature lower in the winter because the house is a more evenly balanced temperature. It was not a cheap experiment but I wish I had done this a long time ago and it was worth the expense.