ISO VG is an acronym that stands for the International Standards Organization Viscosity Grade. Generally speaking, oils classified as an ISO VG (n) oil are limited to industrial lubricants.
ISO VG 2 lubricants for industrial and manufacturing applications are most commonly used to lubricate spindles found in machine tools, which are rotary units found in industrial machines that often work in groups and may operate at both high and low speeds. These oils may also be implemented in some air-powered tools.
ISO VG 2 oil has a midpoint kinematic viscosity of 2.2 mm2/s, also referred to as centistokes (cSt). The midpoint is derived by taking the average of both the minimum and maximum kinematic viscosities. In the case of ISO VG 2 oil, those numbers are 1.98 cSt and 2.42 cSt, respectively. These numbers refer to the standard testing mechanism used to determine how much resistance to flow (i.e. viscosity) these oils demonstrate.
As is always the case with industrial lubricants, the weight is the single most import factor in determining whether or not an oil will suit your application.