We all remember our first folding knife or pocket knife.The all steel construction of this Engineers Knife tells me it was likely made after 1942 when the US began rationing materials like brass and nickel silver so that they could be used elsewhere in the war effort. Everything on this knife; blades, shield, bolsters, springs, bail and pins are made from steel. This is easily verified by the use of a magnet. It has bone handles, the rear handle is a couple shades lighter than the mark side handle, and this is typical of the knives from the early part of World War II. They were making knives for the war effort, not thinking about what would look best to future generations of collectors. These were mass produced war knives, made by some of the world’s finest cutlers, a dying breed at that time and now lost forever.. The Navy spec number was 41-J-4 and the army spec number was 17-170. The military name is “Knife, Pocket, Engineer, Four Blade, With Clevis.” Camillus made 1.7 million of these for the U.S, Navy and 3.2 million for the U.S. Army.