Niobium Wire, 21 Gauge AWG (21ga/.029 inch/.7366mm diameter), 5 Feet (60 Inches/1.524 Meters minimum) Coil (Natural - Unanodized) Unannealed Niobium metal is physiologically inert, making it 100% safe for use in the human body. (It is even used in medical devices such as pacemakers.) Niobium by its very nature is PURE, meaning it is not an alloy, or mixture, of other metals. Niobium is beyond hypoallergenic, it is NON-allergenic. It does not react to body temperatures or moisture. You can swim and shower, and even sleep with Niobium metal in your piercings. Shiny, smooth finish. Niobium is even more gentle in piercings than titanium because of its smooth finish. (Titanium has a slightly abrasive finish). Niobium surpasses all other metals in terms of bio-compatibility. Even people who have reactions to Gold can wear Niobium in their piercings. Unannealed temper. Unannealed is comparible to, and perhaps slightly stiffer than, half-hard temper. Anything you can do with precious metal wire, or even craft wire, you can do with Niobium. Color: Niobium metal in its natural state is a beautiful lustrous dark silver color. The color within a length of any given 5-foot piece may vary slightly from light to dark or shiny to very shiny. This is a normal variation within the product. The changes are subtle and gradient in nature. 21 Gauge, slightly thinner than 20 gauge, perfect for smaller piercings.