Sharpening stone (abrasive grinding wheel) for slicers, size 50 × 12 × 10.2 mm (diameter × thickness × centre hole). It is the wear part of the built-in sharpener assembly that restores the edge of the circular blade. For Italiana Macchi slicers and compatible models; oversized 10.2 mm centre hole. Coarse grit: it removes more metal and restores the edge profile on worn or nicked blades; it is the first wheel in the sharpening cycle, followed by the fine grit. Replace the stone when it is worn out, glazed or no longer bites. Check the three dimensions (diameter, thickness, hole) on your machine: they determine compatibility regardless of brand.