Smith's Edgeware Diamond Elite Pull-Through 7950085 Reversible and Replaceable Diamond and Ceramic Stones For sharpening both Straight / Serrated knives as well as two stages for Santoku double beveled knives. Coarse sharpening slots feature preset diamond rods that quickly sharpen the knife at the correct angle every time Ceramic stones provide the finest of sharpening to finish the knifes edge Provides Proper Sharpening Angle Every Time