Garnet abrasive is used on 95% of all waterjet machines. The size of the garnet abrasive typically used today for waterjet cutting ranges from 50 mesh to 220 mesh, with the most common being 80 mesh. Mesh values do not represent particles of an exact dimension, but represent a distribution of particle sizes. An 80 mesh abrasive will have some particles larger and smaller than exactly 80 mesh. Mesh sizes are usually determined by allowing abrasive to fall through a series of screens – each screen smaller in mesh size from top to bottom. A known quantity of abrasive is placed on the top and vibrated for a fixed period of time, and then the amount of abrasive on each screen is weighed to obtain the distribution.