DMT D11X 11.5-inch Dia-Sharp  Bench Stone - Extra-Coarse Superior diamond sharpening stones Legendary quality Made in the USA Guaranteed not to hollow or groove, precisely engineered, assures consistent, even sharpening every time. Extra-Coarse diamond to repair a damaged 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