The MinoSharp Deluxe Whetstone has been specially developed for use with professional quality kitchen knives. If you follow the detailed instructions enclosed in the packaging, you can achieve spectacular results, even exceeding the knives, ex-factory sharpness levels It is the recommended way to keep your knives in the best condition for use. This stone features 2 different grits - 220 and 1000. The 240 grit is classed as a "course" finish, and should be used when knife blades are chipped, damaged or completely blunt. The 1000 grit is classed as a "medium" finish and is the main stone for sharpening knives which have become blunt. The Profesional Knife Sharpening Kit by MinoSharp includes a deluxe whetstone, plastic holder with non-slip feet which doubles as a storage case and guide rails to keep the optimum sharpening angle. This stone features 2 different grits - 220 and 1000. The 240 grit is classed as a "course" finish, and should be used when knife blades are chipped, damaged or completely blunt. The 1000 grit is classed as a "medium" finish and is the main stone for sharpening knives which have become blunt. The Profesional Knife Sharpening Kit by MinoSharp includes a deluxe whetstone, plastic holder with non-slip feet which doubles as a storage case and guide rails to keep the optimum sharpening angle.