Product review (4 stars): Good but dimensions are inaccurate
I like the product but dimensions on schematic are inaccurate with respect to the chimney portion.  The schematic indicates it is a square 11.7 x 11.7.  Actual dimensions are rear 12 inches, sides are 10 1/4 inches.  Front is not square, it is convex so overall dimension from the back(against the wall) to the farthest forward part of the curve is 12 3/4 inches.  I was installing mine below a soffit and just got lucky that my soffit was almost exactly 12 and 3/4 inches deep so the curve of the chimney does stick out in front of the soffit but maybe only 1/32 of an inch otherwise I would have had all the hassles of returning the product.  I like the product but hey seller, accuracy matters.