Sharpening stone (abrasive grinding wheel) for slicers, size 45 × 8 × 8 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 FIA Boston slicers and sharpeners that use this size. Fine grit: it finishes the cutting edge and revives the blade edge; use it after the coarse-grit wheel for a clean cut. Replace the stone when it is worn, glazed or no longer bites. Check the three dimensions (diameter, thickness, hole) on your machine: they determine compatibility regardless of the brand.