The P-38 and P-51 can openers are a must have for an emergency if you need to open cans. The P-38 was originally developed in 1942 and was issued to U.S. troops so they could open canned C-rations. Later a larger model was developed, called the P-51 which is easier to use because of its larger size. The P-51 is ideal for those #10 cans used in emergency preparedness freeze dried food. Don't be caught without a can opener when an emergency situation occurs. Both the P-38 and the P-51 come in a two pack. Carry one on your key ring so you are always prepared.