The original Redi-Edge Knife Sharpener is unmatched in its design and effectiveness. The convenient Inchstick Inch design gives you a sturdy grip while you use the Duromite cutters to put the perfect edge on your knife every time. The Redi-Edge Original's Duromite cutter blades are factory-set at a 40 degree inclusive angle, maintaining a consistent 20 degree double edge on your knives.