Stainless steel ranks among the most popular and most commonly used material for watch cases. With a hardness of 700 Vickers, steel is indeed a strong substance. This fascinating “heavy metal” is now available in numerous variants, all of which contain the chemical element iron (Fe), which has a specific gravity of 7.86 grams per cubic centimeter, melts at 1,539° Celsius, and boils at 3,000° Celsius. Tough, antimagnetic, and corrosion-resistant alloys of stainless steel are suitable as material for watch cases. The alloy designated by the number “316” is second only to “304” as the most commonly fabricated variety of steel: 316 steel plays an important role in industrial applications and as well in stainless steel watches. Molybdenum improves the resistance to corrosion of this alloy, which is also known as X2CrNiMo18-14-3. The variety termed 316L is a carbon-poor variant, whose austenitic structure provides it with a high degree of toughness, which it preserves even at low temperatures.