DMT D11E 11.5 Inch Dia-Sharp Bench Stone - Extra-Fine 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 Extra-Fine diamond to polish and refine an 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