ISO 2781:2008 specifies two methods of test for the determination of the density of solid vulcanized and thermoplastic rubbers. Such determinations are of importance in the control of the quality of a rubber compound and in the calculation of the mass of rubber required to produce a given volume of material. The standard does not cover the determination of the relative density of rubber, which is the ratio of the mass of a given volume of rubber to the mass of an equal volume of pure water at a given temperature.