ISO VG (International Standards Organization Viscosity Grade), AGMA (American Gear Manufacturers Association), and SAE (Society of Automotive Engineers) all represent the different testing methods used to determine oil viscosity
ISO VG 680 oil has a midpoint kinematic viscosity of 680 mm2/s, also referred to as centistokes (cSt). Always be sure to consult OEM specifications to be certain that you are choosing the right oil for your machinery.