This incredible black 8mm comfort-fit Cobalt band features a hammered finish with a high-polished center cut down the middle and bold round edges.Wow him with the stealthy look of this unique wedding band. Crafted in satin-finished and polished black ion-plated cobalt, this dramatic 6.0mm-wide bevel-edged style says it all. Custom-made to fit his ring size. Cobalt bands cannot be resized after purchase.4x harder than Platinum, 5x harder than Gold and 7x harder than Silver: Cobalt is the ultimate contemporary metal. Benchmark’s naturally inert Cobalt contains a special blend of Cobalt and other alloys that exude extremely high luster and reliable strength. Because it is also hypoallergenic, scratch resistant and biocompatible, it has been used heavily in medical applications. Cobalt, unlike Tungsten, is shatter proof.