If you're preparing for stuff to hit the fan or just want an easy way to open cans while backpacking, the P-38 Can Opener and P-51 Can Opener are inexpensive and lightweight options.
Though it is not an official US Army-issued item, the P-38 and P-51 can openers have been used by our armed forces since they were first introduced in 1942. Nicknamed the "John Wayne" and manufactured by the US Shelby Co. in the United States, these can openers get their name for how long they are. The P-38 is 38 millimeters long. The P-51 is 51 millimeters (about 2 inches).
These durable slabs of steel fit on a keychain. There are many websites devoted to celebrating this can opener, and the list of uses is virtually endless. US Shelby advertises the P-38's ability to clean fingernails, clean grooves, open cans, open seams, screw drive, and cut items.
For can opening, you rotate the cutting edge 90 degrees from the stowed position. You then hold the can opener with the blade directed downward and rotate the can with your other hand as you cut the lid off.
The P-38 and P-51 can openers are a little too novel for the expert sites to review. Instead, it is a popular tool among survivalists and veterans. Infinite Power Solutions recommends the P-51 for people looking for a foolproof, robust, indestructible, lightweight, and reliable can opener for emergencies, backpacking, bug out bags, survival situations, hunting, and camping. Best Survivalist Tools rated the P-38 and P-51 as the top survivalist can openers.
Around 93% of the reviewers on Amazon gave these can openers four or five stars. Users said that the P-38 takes about twice as long to open cans as their cranking counterparts. Also, there appears to be a little bit of a learning curve and a need for elbow grease. Yet, users are thrilled with them once they get the hang of these can openers. Many keep their P-38 or P-51 on them at all times and use them as a flat blade screwdriver, to open battery compartments, for cutting string, and for opening packages.
Pros: 75-year track record, compact, inexpensive
Cons: Works slowly, requires a little elbow grease, leave sharp edges
Buy the P-38 Can Opener and P-51 Can Opener on Amazon for $4.05 (originally $5.48)