Sharpening stone (abrasive grinding wheel) diameter 51 mm, fine grit for RGV slicers. Wear part for the built-in sharpener assembly. The fine grit finishes the cutting edge and revives the blade edge: it is used in the second stage, after the coarse-grit wheel (51 mm coarse-grit version), for a clean cut with no burrs. The two grits work as a pair in the sharpening cycle: keep both and replace the stone when it is worn out or glazed. Check the diameter (51 mm) and the mounting on your RGV model before purchasing.