Smith's 4" Diamond Combination Sharpener features coarse and fine grit sharpening surfaces. The coarse diamond stone easily sharpens dull or damaged knives and the fine diamond stone puts a final razor-sharp edge on your knives and tools. These surfaces contain multiple layers of micron-sized monocrystalline diamonds and a unique sharpening surface with an interrupted surface hole design. This innovation speeds sharpening by collecting and holding the metal filings which ordinarily build up during the sharpening process. Each stone has a "micro-tool sharpening pad" and a sharpening groove for fish hooks or pointed tools. The soft grip rubber handle is designed to make sharpening safe and easy, and when you are finished sharpening, you can store your stones in the handle for safekeeping.