This 2-stack channel & diamond square ring set is rigid, yet extremely comfortable due to its softly rounded edges. This stack is made up of two rings including 1 thick (6mm) channel square ring with a 1.5mm diamond and 1 thick (2.5mm) silver square ring. This stack is available in sizes 5.0-9.5, including half sizes. Special note: Because of the width of our stack ring sets, it is recommended to buy a stack that is approximately a half to a full size larger than your normal ring size. Materials: Sterling silver (.925), oxidized sterling silver, and a lab-created diamond. 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 set is designed in San Francisco and handmade in our Upstate New York production studio.