Military history is full of iconic, dependable products whose cultural impact can be felt for decades. The P-38 is one of those products. Rather, judging from veterans’ opinions on the can opener, it might be the iconic, dependable product. The only other tool we’ve heard talked about as highly as the P-38 (named for the 38 punctures needed to open a C-Ration can) might be the M1 Garand, which, if you’ve ever heard a vet talk about their old battle rifle, you know is high praise.

It’s an unassuming piece of kit. It’s exactly an inch and a half long and has a folding blade. That’s it. That’s the whole description. But it made a hell of a difference.

The P-38, affectionately known as a “John Wayne,” most likely because of its toughness, saw action throughout the 21st century, beginning in World War Two and carrying all the way through to Desert Storm, roughly fifty years of constant service. Even though it’s out of official production—C-Rations having been declared obsolete—there are soldiers and veterans carrying these can openers with them today. Clearly, the military did something very right with the P-38.


The military included can openers in previous ration kits, but the fatal flaw in these was always the lack of a reliable locking mechanism. That’s why C-Rations didn’t have the P-38 when they first came out. Instead, food tins were opened with a winding key system, which worked, but proved to be prohibitively expensive. When the war kicked up, those costs started building fast and the military needed something that could do the same job for much, much cheaper.

Making a cheaper can opener fell to the Subsistence Research and Development Laboratory (SRDL) in Chicago, a lab tasked with modernizing the US military’s food supplies and technology. It’s the group responsible for the C-, K-, and D-Rations and 5-in-1 and 10-in-1 mess kits, basically keeping American forces fed in Europe, the Pacific, Korea, Vietnam, Kuwait, Iraq, and anywhere else American forces found themselves between 1942 and the mid-1980s.

The lab was headed up by Colonel Roland A. Isker, an officer who’d been with the Army for years and had been deployed all over the world, but it was Major Thomas Dennehy who invented the “Opener, Hand, Can, Folding, Type 1,” the official designation of the P-38. It took him only thirty days over the summer of 1942, making it the antidote to those constant stories about government inefficiencies and spending a million bucks on inventing a pen.

We don’t want to leave out anyone important to the P-38’s invention, so we should definitely mention John W. Speaker, an Austrian immigrant working in his own metal shop in Milwaukee. The main problem with previous ration can openers was their lack of a locking mechanism, meaning they’d open and stick their owners or rip clothes. Speaker invented the “detente,” two lugs that protruded and held the blade closed, making the P-38 possible in the first place. And in the spirit of hating Hitler a whole goddamn lot, Speaker filed his patent as a royalty-free, nonexclusive contract, which meant anyone could use the design for free, allowing manufacturers to pump out as many P-38s as they possibly could.

And there were a lot of them. So many no one could keep reliable records of their production. Speaker, the man who ran the company that made P-38s for the longest time, estimated he produced 50 million of the tools, and he was only one of 12 companies to manufacture them. The P-38 was so easily produced, it’s estimated it only cost one cent to make 10 million at a time.

In Action

Like we said in the intro, it doesn’t seem like vets have anything bad to say about the P-38. It’s a unanimous glowing review of the tool, on par with the legendary M1 rifle. Soldiers through the Second World War, Korea, and Vietnam credit the P-38 with saving their lives in and out of combat.

Obviously the can openers opened cans of food and did so extremely well. A Czechoslovakian couple sent a letter of thanks to the American Embassy in Prague and enclosed a P-38 inside. We’d summarize their letter, but there isn’t a better endorsement of the main purpose of the can opener, so here it is in its entirety.

In 1945 we received two of these can openers from UNRAA relief parcels which your country used to send to Europe to help overcome shortages after World War II. We have used these two can openers for the entire duration of our marriage, even though we tried to replace them with new ones several times. You can just imagine the number of cans of all types which we have opened for the 40 years, without a single problem. New openers did not last too long, they worked only a few times, but the UNRRA openers still work like new. We are sending you one of them in order to prove what we are saying and for the possible identification of a manufacturer so that you might thank them on our behalf. Every time we use the can opener we think about the unselfish assistance of American during and after WWII when in addition to arming the world against Fascism, she lost a large number of her sons, sons who lost their lives fighting for our freedom. We can never forget these things.

This was obviously a product that opened cans without any problem.

But if you leave something simple and accessible in the hands of men who don’t have the normal tools and luxuries they’re used to, they get creative quickly. It was in that creativity the P-38 showed its true value. In effect, the US military had packaged the most versatile multi-tool ever made in its standard issue C-Rations.

First and foremost was portability. A small hole punched in the opener was originally intended for cleaning. You’d put it on some string or wire and dip it into boiling water, getting dirt or your previous meal’s gunk off the tool. But men quickly figured out you could put the P-38 on your neck right next to your dog tags, guaranteeing easy access.

According to John Bandola, a Second World War veteran who served in North Africa, “The P-38 was our means for eating 90 percent of the time, but the next thing I knew we were using it for cleaning boots, fingernails, screwdrivers, you name it. And we all carried it on our dog tags or key rings.”

In Korea, soldiers found the tool perfect for field stripping the beloved M1. Jay Welsh of the 24th Infantry Division, fighting on Papasan Mountain (not the Korean name), said the P-38 “was the ideal tool to field strip and clean the finer components of the M1 rifle. I believe that two-piece hinged device saved my life. It assured me I had a rifle that would fire.”

Two vets from Vietnam, Ted and Paul Paquet were driving down Route 60 when their car started acting up. “There were no tools in the car and almost simultaneously both of us reached for P-38s attached to our key rings,” Paquet said. “We used it to adjust the flow valve and the car worked perfectly.”

There are even stories of soldiers stringing P-38s up on Christmas trees to try and bring some holiday spirit to their personal slices of jungle hell.

Plenty of the can openers ended up as heirlooms too. If you went over to active duty soldiers today, wherever they are, it’s a guarantee you’ll find someone carrying a P-38. Most likely it’s one their father or grandfather carried with them through their military service. It’s an enduring, well-designed object of perfection that performed above and beyond anyone’s initial expectations. The military thought it was building a better can opener and ended up commissioning a legend.

If you’d like to add the P-38 to your own collection of EDC (or replace everything with it), head over to the Cool Material Shop


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