Lyemance Damper Size(in) Outside Base Dimensions(in) Fits INSIDE Flue Widths of(in) Fits INSIDE FLUE Lengths of(in) Damper Height When Open(in)
8 x 8 9 1/4 x 9 1/4 6 1/2 - 8 1/2 6 1/2- 8 1/2 3 1/4
8 x 17 9 x 17 1/2 5 3/4 - 8 1/4 14 1/2- 16 1/2 5
9 x 13 9 1/2 x 13 6 1/4 - 8 1/2 8 1/8 - 12 1/8 4 1/4
12 x 16 12 5/8 x 16 1/8 9 1/4 - 12 12 3/4 - 15 5 1/4
13 x 13 13 x 13 10 - 12 1/2 10 - 12 1/2 5
13 x 18 12 3/4 x 18 10 - 12 1/2 15 1/2 - 17 1/2 5
17 x 17 18 x 18 15 - 17 1/2 15 - 17 1/2 6 1/2
12 Round 13 7/8 10 5/8 - 11 3/8 10 5/8 - 11 3/8 4 3/4