MKS system of units
The MKS system of units , also called the MKS system for short , is an absolute metric system with the three basic units meter ( m ), kilogram ( k g) and second ( s ). By adding the ampere ( A ) as the fourth base unit, the MKSA system was created in 1939 . This system was incorporated into the International System of Units ( SI ) in use today in 1960 .