Redi-Edge Knife Sharpener has been manufactured in the United States by Klawhorn Industries, Inc. since 1994. The sharpener has met the discriminating requirements of cutlery enthusiasts around the world.The Challenge Coin Knife Sharpener is unmatched in its design and effectiveness. The convenient "challenge coin" design enhances the portability of the sharpener. Its Duromite inserts are harder than any knife blade; and factory set at a 40 degree inclusive angle, maintaing a consistent 20 degree double edge on your knives. The Challenge Coin is produced from military-grade aluminum for extreme durability, long life, and lightweight. This Marine Corp model has a black finish and is engraved with the USMC logo on the front and the Eagle, Globe and Anchor on the back.