This is the civilian Buck 188. A total of 14,495 were produced with the 1987 date code in two variations, the three and the four line version. This one is the four line version which includes the Pat Pend. It also has a Rockwell hardness test dimple behind the cutting hole on the Phrobis tang stamp side. This one is in exceptional condition with very little wear from going in and out of the sheath. A very complete knife that comes with the sheath in beautiful condition and with the papers in the box.