This 4mm wide black or silver "densa" square band is available in sizes 4.5 - 9.5, including half sizes. Material: Sterling silver (.925) or oxidized sterling silver. All materials are hypoallergenic. The black (oxidized) components of our jewelry will wear over time and eventually achieve a beautiful antique-like finish. This ring is designed in San Francisco and handmade in our Upstate New York production studio.