These multi-flue tops are 100% copper, except for the screws and base which are copper-plated stainless steel. The 8" hugh screen is 18-ga. copper 3/4" mesh, and the lid is 24-ga. copper. Tapcom masonry screws are included. All of our copper caps come with a lifetime warranty. Please note: Copper Chimney Caps are not recommended for installation on white or light colored chimneys, as they may cause yellow streaks. These copper chimney caps have a beautiful color when new, which changes to a rich patina as they weather, and changes further to the much desired Statue of Liberty green as they age.