Benchmark Alternative Metal Seranite 7mm Double Center Ridge Satin Men's Ring, Benchmark #CF57444CM. This ring is made of a satin finished seranite black ceramic with a flat, double ridged center. Width is 7mm. Crafted of scratch-resistant and lightweight high-tech ceramic. Known for its durability and highly polished material. Ceramic doesn’t scratch, craze, discolor, or fade. It is hypoallergenic, contains no cobalt, and is greatly resistant to chipping and breakage.