Sharpening a knife requires a harder material than the material you are trying to sharpen. Our Duromite cutters are harder than any cutlery steel on the market today. The Redi-Edge Pocket Knife Sharpener is unmatched in its design and effectiveness. The convenient "pocket" design enhances the portability of the sharpener and provides a large surface for custom engraving which is available on special orders. The thumb insert gives you a sturdy grip while you use the Duromite cutters to put the perfect edge on your knife every time. The Redi-Edge Pocket's Duromite cutter blades are factory-set at a 40 degree inclusive angle, maintaining a consistent 20 degree double edge on your knives.