The ceramic mill on the pepper mill is placed on top to avoid pepper spilling onto the tablecloth. The mill can be set to grind finely or coarsely. It works on the same principle as a pestle pounding the taste out of the pepper. The unique, ceramic grinder mechanism is from CrushGrind, which is known for its high quality and for the degree of grinding which can be easily adjusted, so you get the spices just the way you want them. There is a 25-year guarantee on the ceramic parts in the grinder.