Tungsten Carbide is one of the hardest metals. It is polished to a mirror-like finish and retains its shine over time. Tungsten is much harder than metals like 18K gold, tool steel, and titanium. Its reflective surface offers a sparkling luster, a mirror-polished finish, and excellent corrosion resistance. All of our rings are made from genuine Tungsten Carbide and engraved for authenticity. This product is designed for comfort fit and contains no cobalt, making it a durable and hypoallergenic choice. The 4mm Galaxy Opal Black Tungsten Ring features a blue galaxy opal inlay, black IP plating, a dome shape, and is available in sizes 5-10, including half sizes. Each ring comes with a complimentary ring box.