For Factory Build Air Cooled Triple Wall Chimneys. 2-Piece Design 24 gauge removable hood with built-in 9 height screening. Raise inter collar lets double and triple wall chimneys ventilate properly. 1/2 inch inside lip prevents water from rolling back into the flue. Superior animal proof 3/4 oval hole mesh prevents creosote build up. Outer base fit over the outside of your chimney, while the 4 long sleeve slips inside the chimney flue. Made in the USA. Not imported from China or India. To find the right size cap for your chimney see the chart below. 6″ round: Sleeve is 5-7/8″ Outer ring is 13-1/4. 7″ round: Sleeve is 6-7/8″ Outer ring is 13-1/4. 8″ round: Sleeve is 7-7/8″ Outer ring is 13-1/4. 9″ round: Sleeve is 8-7/8″ Outer ring is 17-1/4. 10″ round: Sleeve is 9-7/8″ Outer ring is 17-1/4. 12″ round: Sleeve is 11-7/8″ Outer ring is 17-1/4. The free listing tool. This item is in the category “Home & Garden\Home Improvement\Heating, Cooling & Air\Fireplaces & Stoves\Fireplace & Stove Accessories”. The seller is “capman73ug” and is located in this country: US. This item can be shipped to United States.