Our Niobium Hoop Earrings are either made of pure Niobium wire or dangle from pure Niobium ear wire hooks. Pure Niobium is sometimes denoted as 999 Niobium. It is naturally nickel free, chromium free, and cobalt free. Niobium is ultra comfortable and often people remark that they forget they are even wearing earrings while they are wearing Niobium. Our Niobium ear wire hook styles come with plastic safety ear nuts to keep the ear wires securely in place.