When the power is out in the next storm, a P38 or P51 can opener can save the day.
Our US military has been using them for countless years.
 
A P-38 will work with any size can
Perfect for Camping, Hiking, Fishing, or the Survivalist in your Family
Attaches to your Key Ring, Dog Tag, Tackle Box, or in your Emergency Survival Kit or Truck Kits or just put one in your Hunting bag.
Tape one to each can in your Grab and Go Bag or Emergency Stockpile.
I know people that carry one as part of their EDC and have one on their key chain daily and are never caught without one. Probably the cheapiest thing you can carry that can save your life!

Added Educational Note: 
The P-38, developed in 1942, is a small can opener that was issued in the canned field rations of the United States Armed Forces from World War II to the 1980s. This is the one our soldiers used to carry!

The P-51 (51mm in length) is the big brother to the P-38 Can Opener. It was designed in the 1980s as the big brother to open #10 cans and the large 36 soldier meal pack or T-Packs. About twice the size of the P-38 but about twice as easy to use due to it's larger handle.