The P-51 is the larger version of the P-38 and was often used by mess hall cooks to open the big trays and large cans of chow. The P-51 is a full 2" long. The added length affords more leverage and doesn't require as much thumb pressure to use. Some prefer them over the P-38s because a P-51 will open cans much easier and faster and will last much longer than the P-38. We recommend having one in every car, on every key-ring and included in every emergency survival kit.