Galvanized steel chimney cover to prevent animals from entering or nesting in your chimney. 24 Gauge Single Piece Galvanized Steel Hood with scalloped corners and drip edge. 14 Gauge Galvanized Steel Base for extra strength. 18 Gauge 3/4" expanded galvanized steel mesh. If flue tile does not extend above the crown leg kits are available for mounting. Model CBO1818 inside diameter measures 18" Long x 18" Wide.