This is a Very Attractive Well Made Tungsten Ring for Men and Women. It's Cobalt Free to avoid allergies and has the Carbides to make them Scratch Resistant. The curvature inside the ring is carefully measured and perfectly polished to provide a true comfort fit. A word of caution; tungsten material as hard as it is, it's a bit brittle and can shatter if it falls on hard surfaces such as porcelain tiles.