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 Shield Knot Viking Norse Rune Minimalist Oval Top Polished Statement Signet RingSurgical Grade Stainless SteelEngraved Shield Knot Viking Norse Rune DesignApprox. Top Dimension: 0.41 inch x 0.45 inch (10.5 mm x 11.5 mm)Standard Fit WearPolished Finish Minimalist Style