Case XX Knife Pattern
The Copperhead pattern is a jack knife with a Clip master blade and a Pen secondary blade. The pattern is known for the distinctive shape of the pocket end bolster, which extends upward to cover the sharp corners observed while looking at the back of the blade tangs. The tang is recessed, eliminating the edge, which could cause pockets to wear out. This pattern is often called a "Viet Nam" as it was very popular among GI's during the Viet Nam War.