1. Balls:

They are usually made of steel, chrome or ceramic materials and grind the material as they rotate in the mill.

2. Cylpebs:

Cylindrical or short cylindrical parts, usually made of steel and used to grind the material.

3. Conpebs:

Conical in structure, usually made of steel and used to grind fine materials.

Grinding media,

is in constant contact with the material inside the mill and provides impact, friction and shearing movements to reduce the size of the material. Properties such as surface area and mass affect grinding efficiency.