This is the 1.7 X 1.7 Inches (4.3 X 4.3 cm) Gate Fence Post Cap. Made of galvanized steel, giving your gate or fence a better finished look, which will keep away dirt and rain from getting inside your posts.... What is Galvanized Steel? Galvanized Steel is iron that has been through a chemical process that protects the steel from rust and corrosion. The steel is submerged in molted zinc. This process known as galvanizing, permanently bonds the zinc to the steel. The zinc is now a shield for the iron. Metal: Steel Galvanized. Ball Diameter: 1.5 inches (3.8 cm). Set of 2 Caps.