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 240 Grit stone is classed as a "course" finish, and should be used when blades are completely blunt, or blades are chipped and damaged. 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.