Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives regarding pressure are specified in the unit bar. Though the bar is not a SI unit like the pascal, nor a cgs unit, it is accepted for use with the SI by the US National Institute of Standards and Technology. The bar is widely used in descriptions of pressure because it is only about 1.3% smaller than "standard" atmospheric pressure, and is legally recognized in countries of the European Union. Conversion between the units bar and the MPa is however easy since 10 bar = 1 MPa. If there are any contradictions between new decisions and preceding decisions adopted at
International System of Units and derived units may be used to express other derived units. For example, the SI unit of force is the newton (N), the SI unit of pressure is the pascal (Pa)—and the pascal can be defined as one newton per square metre (N/m). Prefixes are added to unit names to produce multiples and sub-multiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand. For example, "kilo-" denotes a multiple of a thousand and "milli-" denotes a multiple of a thousandth, so there