A case covers the movement, dial and hands. The size of the case is usually fit the size of the movement. Assembled with different case-back and glass determines the level of waterproof. There is all different kind of shapes of cases as long as there are movements for the shapes.
The common materials of cases are:

We usually uses PVC or PC as materials. It’s softer than other materials.

Using zinc as the main material combined with other elements. The specialties are low-melting point, good liquidity, easy to shape, good corrosion resistance and light.

In the actual usage, stainless steel is weak corrosion resistance, it is not necessary to be all chemical resistance. The level of its corrosion resistance accords to the elements it combined with to fit the usage of the case. (the elements include nickel, molybdenum, niobium, copper, nitrogen)

• 304 is a common stainless steel. It is strong corrosion resistance and easy to process.

The specialty about fine steel is the color will never fade, the shape will never be deformed, and it is harmless to the skin and environment. It is really shiny and looks good. They mainly are:

• 316L is stainless steel, strong corrosion resistance and looks really good. It is usually harmless to the skin. Swiss watches use this material in cases, pushers and bands.

Pottery and porcelain cases are usually very shiny, abrasion resistance, stable physical characteristics, acid-alkali resistance, corrosion resistance, light, harmless to the environment and the color of it is not easy to change. It is harmless to the skin, comparing to the stainless steel with nickel which is bad to our skin. The weakness of it is it can only be shaped in round; it is pretty fragile as well.

Tungsten steel is very different from usual watches’ material. It’s almost as hard as diamond, as shiny as mirrors and the color of it will never fade.