Considered “The Army's Greatest Invention”, this amazingly simple 1-1/2 inch stamped metal device was developed in Chicago during the summer of 1942 by the Subsistence Research Laboratory for use by troops during World War II.
The P38 supposedly acquired its name from the 38 Punctures required to open a C-Rations can. The Navy and Marines also gave it the name “John Wayne” because he was shown in a training film opening a can of C-Rations.
Officially designated 'US Army Pocket Can Opener' or 'Opener, Can, Hand, Folding, Type 1,' it adorned the dog tag chains and key rings of WWII, Korean, and Vietnam vets ever since they opened their first can of C-rats.