Rain Cap for round double or triple wall flue ID x OD = 8 x 12.5, stainless chimney cap

I have a double wall chimney, unfortunately it doesn't explain that the 8" inner wall size only works if you have an inner wall that is 8". My outer wall matches the measurements of the 12.5, but after installing it, we got smoked out because the inner circle reduced the air flow. Had it not had that inner circle (they don't show that on the picture) it would have been fine, now that we have used it, we are stuck with it, probably will try to modify it somehow as the outer ring clamps on just fine...So if you inner wall is larger than 8", don't purchase this one......high quality piece!

My chimney stack is atypical of what is out there and thought after searching for a cap that there was no hope. But I found this gem and it had all the same metrics as my stack so I went for it. The design measurements listed fit right on with what I measured on my stack. In addition, this was the only one I can find that was stainless. All others offered only in galvanized. I'm a coastal Florida home and the old one was galvanized and didn't hold up well.

Replaced a destroyed cap on a modular with this, perfect. Took more time getting the ladder than installing this unit. Very well constructed, nice work.