Manufacturer's code: 820667 Japanese stone to sharpen Hendi by Naniwa, Used to sharpen knives. The sharpener is double-sided and combines two tiles of various grain (220/1000). The grain of 220 is used to grind and regenerate the edge of the blade, and the grain of 1000 will serve to sharpen the blade base. Before use, you must go down the stone. For safe storage, a plastic container is included in the set. Product features: