DMT D3EFC  3-inch Dia-Sharp Sharpener, Credit Card Sized- Extra-Fine, Fine and Coarse Diamond -Set of 3 Pocket-sized convenience Three different diamond stones: Extra-Fine to polish and refine an edge, Fine for a razor sharp edge and Coarse to transform a dull edge Sharpens knives faster than conventional stones with DMT's micronized monocrystalline diamond surface No oil is needed-sharpen dry or with water Durable construction will provide years of performance and reliable service Pocket-sized convenience 3 different diamond stones--extra-fine to polish and refine an edge, fine for a razor sharp edge, and coarse 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