The Hunter Honer"s Nitrided Rods are expensive to harden and make, 70 on the Rockwell C scale and Guaranteed for Life, both Flexable Rods are turnable after 5 years of use at the points of contact. The Rods will quickly sharpen all knives and metals without destroying them, using our patented flex designed and sharpening techniques. Hunter Honer will sharpen hard steel knives like D-2, AUS, ATS-34 and Buck 110 knives in seconds. Most knives are not as hard as these knives which range from 59 to 64 on the Rockwell C scale. However, many great stainless steel knives range between 54 to 58 on the Rockwell scale and the Hunter Honer sharpens them to the best smooth cutting edge. But, High Carbon steel knives still get the sharpest knife edges, however, these knives may rust if not properly taken care of.