DMT W250EFNB 10-Inch DuoSharp Bench Stone Extra-Fine / Fine Legendary quality Made in the USA Precision flat, two-diamond surfaced sharpener guaranteed to provide consistent, even sharpening every time Two sided: Fine diamond for a razor sharp edge and Extra-Fine 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