At TIONEER, we use surgical grade stainless steel for our massive selection of metal jewelry. Surgical grade stainless steel is abundant in our collection due to its hard body, incredible resistance to corrosion and tarnish. Stainless Steel Akechi Samurai Crest Geometric Pattern Step-Down Biker Style Polished RingSurgical Grade Stainless SteelEngraved Akechi Samurai Crest DesignApprox. Top Dimension: 0.63 inch x 0.57 inch (16 mm x 14.5 mm)Standard Fit WearPolished Finish Style