The WÜSTHOF 10" Diamond Sharpening Steel is a sharpening rod with a diamond coating that should be used to sharpen dull or moderately sharp knives. The special shape of the diamond grit on the sharpening rod ensures exceptional sharpening of the knife blade. The result: a smooth, sharp edge. As these rods remove a tiny amount of metal from the knife, we recommend using a WÜSTHOF honing steel for daily or weekly edge maintenance. Diamond sharpening rod fine = 240 grit (European standard); width 19mm (0.75")