The document describes several models of planetary ball mills from Fritsch, including the PULVERISETTE 5, 6, 7, and 4 classic line mills. The mills are suitable for fine grinding and mixing of samples down to the colloidal range for applications in industries like geology, chemistry, biology, pharmaceuticals, and materials research. Key features highlighted include precise speed control, programmable operation, grinding capacities from milligrams to hundreds of grams, and reproducibility of results.