Model Size Fits Minimum Inside Flue Sizes Fits Maximum Inside Flue Sizes
8" x 8" 7" x 7" 10" x 10"
8" x 17" 7" x 15" 10" x 18.25"
9" x 13" 7" x 10" 10" x 13.5"
13" x 13" 10" x 10" 13.5" x 13.5"
13" x 18" 10" x 15" 13.5" x 18.25"
18" x 18" 15" x 15" 18.25" x 18.25"