Draft King CBO10 Round Bolt On Black Galvanized Steel Single Flue Chimney Cap, 10" Diameter For masonry chimneys only. Not for use with air-cooled metal chimney systems. Fits outside tile (inches): 9.5 to 10.5 Round. 24 gauge powder-coated galvanized Steel hood with scalloped corners and roll-formed edges, 18 gauge 3/4 inch 100% galvanized Steel expanded metal mesh Slotted hex-head Steel mounting bolts for easy, durable installation. Outside mounting provides greater free air space. Expanded metal mesh turned inward at base allows cover to rest firmly on flue tile, closing any openings to protect against nuisance wildlife. 7 year limited warranty.