Double Flue Cap Model. 2-Piece Design 24 gauge hood with a one piece and built-in 8 height screening. Superior animal proof 3/4 oval hole mesh prevents creosote build up. 3 depth base compensates for uneven flue tile heights. Made in the USA. Not imported from China or India. To find the right size cap for your chimney see the chart below. 8 x 22 fits flue sizes from 6.5″ x 21″ to 9″ x 24″ Fits over a double flue that includes an 8 x 8 and a 8 x13. 8 x 28 fits flue sizes from 6.5″ x 25″ to 9″ x 28″ Fits over a double flue that has two 8 x13 flue tiles. 13 x 24 fits flue sizes from 11″ x 21″ to 14″ x 24″ Fits over a double flue that includes a 8 x 13 and a 13 x13. 13 x 28 fits flue sizes from 11″ x 25″ to 14″ x 28″ Fits over a double flue that has two 13 x13 flue tiles. The free listing tool.