History of the Swiss Army Knife
Various models of Swiss Army knives exist, with different tool combinations for specific tasks. The simplest model sold includes only a single blade. The most common tools featured are, in addition to the main blade, a smaller second blade, tweezers, toothpick, corkscrew, can opener, bottle opener, slotted/flat-head screwdriver(s), phillips-head screwdriver, nail file, scissors, saw, file, hook, magnifying glass, ballpoint pen, fish scaler, hex wrench w/bits, pliers, and key chain. Recent technological features include USB flash drives, digital clock, digital altimeter, LED light, laser pointer, and MP3 player.
The stainless steel alloy used for the cutting blades is optimized for high toughness and corrosion resistance and has a composition of 15% chromium, 0.60% silicon, 0.52% carbon, 0.50% molybdenum, and 0.45% manganese. After a hardening process at 1040 °C and annealing at 160 °C the blades achieve an average blade steel hardness of 56 HRC. This steel hardness is suitable for practical use and easy resharpening, but less than achieved in stainless steel alloys used for blades optimized for high wear resistance. The steel hardness of other tools varies.

