Chimney Cap Size	Fits Outside Flue Width of	Fits Outside Flue Length of	Screen Mesh Height
8"x8"	6" - 8 1/2"	6" - 8 1/2"	8"
8"x13"	6" - 8 1/2"	11 1/2" - 14"	8"
8"x17"	6 1/4" - 8 1/2"	16 1/2" - 18 1/2"	8"
8"x19"	6 1/4" - 8 1/2"	18" - 20"	8"
10"x17"	8" - 10 1/2"	16 1/2" - 18 1/2"	8"
13"x13"	11" - 13 1/2"	11" - 13 1/2"	8"
13"x17"	11 1/2" - 16 1/2"	13 1/2" - 18 1/2"	8"
13"x21"	11" - 13 1/2"	19" - 21 1/2"	8"
17"x21"	15" - 17 1/2"	19" - 21 1/2"	8"