ECLIPSE Domed Black Tungsten Ring with Polished Offset Grooves - 6mm and 8mm This stunning line of cobalt-free Black Tungsten Rings is quite simply beautiful. This style is a domed black tungsten carbide ring with dual offset polished grooves skillfully machined on to its surface. This ring can be worn as a Wedding Band or Promise Ring by men or women and is available in 6mm or 8mm wide, for couples who want a matching set. Thorsten is proud to present our designer Black Tungsten Carbide Ring line. Please note, Black Tungsten Carbide rings are very durable, but can be scratched. Truly Free Lifetime Sizing and Lifetime Warranty on all tungsten rings, no exchange|sizing fees, which are charged by other retailers.