To open the cans, C-rations came with what many consider the greatest invention—the P-38 can opener. Some say the P-38 acquired its name from the 38 punctures around the C-ration can that were necessary to open it. Another theory is the can opener performed with the speed of the legendary World War II P-38 fighter aircraft. Whatever the origins of its name, the P-38 could do more than open cans. Made of sheet metal, it was just the right size and shape to serve as a tool used to field strip a soldier’s weapon, or pry open a jammed lid. If you ask anyone from the C-ration era, he'll still have a P-38 somewhere,” explained Thompson, who flew both helicopters and fixed-wing aircraft during the Vietnam War.