The HY-C single flue masonry chimney cap is designed to fasten directly to your clay flue tile liner at the top or your chimney. The HY-C chimney cap sits on top of your flue tile, The base is fastened with Stainless Steel Hex Head Screws to the clay flue tile. If you do not have a clay flue tile liner protruding from the chimney you can use a set of Cap Mounting Brackets to fasten the chimney cap to the chimney.