Sharpening a knife requires a harder material than the material you are trying to sharpen. Our Duromiteâ¢ cutters are harder than any cutlery steel on the market today. The original Redi-Edge Knife Sharpener is unmatched in its design and effectiveness. The convenient âstickâ design gives you a sturdy grip while you use the Duromiteâ¢ cutters to put the perfect edge on your knife every time. The Redi-Edge Original's Duromite cutter blades are factory-set at a 40Â° inclusive angle, maintaining a consistent 20Â° double edge on your knives. Trust your knives to the dependable Redi-Edge Original!