Redi Edge Large Redtl 40 Dog Tag Knife Sharpener, Black Features military-grade aluminum construction for extreme durability, long life and lightweight Duromite sharpening elements are harder than any knife blade Factory pre-set to sharpen most knife blades at a 40 degree inclusive angle to maintain a 20 degree double cutting edge Redi-Edge Caramelized coating will protect your sharpener Features Duromite cutters, additional honing surfaces