DMT D11C 11.5-Inch Dia-Sharp Bench Stone - Coarse Superior diamond sharpening stones Legendary quality Made in the USA Guaranteed not to hollow or groove and precisely engineered to assure consistent, even sharpening every time Coarse diamond to transform a dull edge Sharpens knives faster than conventional stones with DMT's monocrystalline diamond surface No oil is needed--sharpen dry or with water Durable construction will provide years of consistent performance and reliable service