I have a wood stove in my 1956 fireplace, with black pipe going up through the existing top-of-the-fireplace cast-iron damper/flue. So, the damper is permanently open and as such, even though I've sealed around the black pipe, I get drafts coming down through the stove (when it's not running). At times, I would come home and the house would smell like chimney/fire even though I hadn't used the wood stove for days. Similarly, with my well-insulated house, when I ran the strong exhaust fan in my kitchen, ice-cold, smelly air would be drawn down the chimney and through the dormant wood stove. Not good.This damper was PERFECT for this situation and frankly should replace every one of the old cast-iron dampers in every fireplace in America since they don't do much to seal off what's basically a wide open HOLE to the great outdoors.It was easy to install - the hardest part is getting on the roof, seriously. You drop the cable down the chimney, check that it swings right when it's sitting on top, and then smear the included goop on top of the clay liner and plop the damper on top. Climb back down, wait for the goop to set and put in a couple of screws for the included bracket to hold the cable out of the way. I can't recommend this highly enough. Seriously; every chimney without one is just a hugely inefficient part of any home.
Easy installation
Good seal
Comes with everything you need
Documentation should include detailed schematic outlining clearances, etc.