Ah, the P38, I have one on my key ring and another still on my dog tags. One from basic, my first c-rat meal and one from a case of c-rats opened on a mountain top outpost outside Qui Nhon. Didn't mark which is which but they both bring back the memories.
My wife and daughter were fascinated the first time they saw me use one of them. Esp since I got my can open before they could mount the "super duper miracle opener" and get a can open.

And as to my dog tags, wrong blood type, if I had been wounded and they went by the tags I would have been in trouble. Seems I have an odd ball sub-type of "A" that the simple quick test will read as "AB". And the Army used that simple quick test when I was processed. I didn't find out about that until I was in for surgery and the hospital did a full spectrum blood workup. The nurse was going over a pre-surgery check list and I told her my Army dog tags had said AB, not A. After the surgery the doctor told me they double checked and found the information about the simple test problem for people with my sub-type of A. He also informed me the military no longer used that old test that gave the false reading.