Spyderco ceramics come in three grits - medium, fine and ultra-fine - none of which require lubricants such as oil or water for use. Each grit serves a different purpose in the sharpening process. The medium grit stone produces a good working edge by efficiently removing steel and reshaping the bevel of a dull cutting tool. The fine grit stone then tightens the scratch pattern, creating a razor-sharp edge. A polished and professionally finished edge is achieved with the ultra-fine grit stone. All of our stones are dishwasher and autoclave safe. In addition, steel particles can be removed from any of the stones using a powdered abrasive cleanser and a nylon scouring pad.