Knives that eventually stop cutting sharp? Very annoying. With a sharpening steel you can straighten burrs that develop over time. However, this does not sharpen your knives. With this ceramic Wusthof sharpening steel does not straighten the burrs, but grinds a small layer of steel off the knife. This creates a new V-mouldon the blade. The sharpening rod also has a higher hardness, making it usable for almost all knives.