The CHIM-A-LATOR line of Chimney Cap Dampers easily mount to the top of a masonry or clay tile chimney top with a simple screwdriver. 100% stainless steel. Proven more reliable than bottom mount cast iron dampers, easier to operate, and more efficient to save your energy dollars from being wasted up the chimney. Six damper handle settings allow you to adjust the damper opening for precise draft control. Note: Do not use top mount dampers with gas logs. Intended for use with traditional masonry wood burning fireplaces. How to Measure Measure inside dimensions of flue tile liner, the use the chart below to determine size needed. Sizes Size Fits Outside Flue Sizes 8" x 8" 7" to 9 1/4" Width x 7" to 9 1/4" Length 8" x 13" 7" to 9 1/4" Width x 11" to 13 1/2" Length 8" x 18" 7" to 9 1/4" Width x 16" to 18 1/4" Length 12" x 12" 10" to 12 1/4" Width x 10" to 12 1/4" Length 13" x 13" 11" to 13 1/2" Width x 11" to 13 1/2" Length 13" x 18" 11" to 13 1/2" Width x 16" to 18 1/4" Length 18" x 18" 16" to 18 1/4" Width x 16" to 18 1/4" Length
