Ansen Tools AS-453 Grit Sharp Premier 8-Inch Double Sided Diamond Sharpener Coarse/Medium with a Non-Skid Rubber Base Double-sided coarse 220 grit-medium 400 grit with advanced monocrystalline technology Guaranteed flat surface will provide years of constant service The coarse diamond grit is ideal for a rough or uneven surface, while the medium diamond grit quickly smooths and sharpens a dull or damaged edge Sharpens the toughest materials including tool steel, carbide, titanium and ceramics Two stage sharpening ideal for cutlery knives, woodworking tools, gardening tools and machine tools