Thus, the balance between frictional efficiency and wear protection can be optimised by the judicious selection of the types of polymer and viscosity grades. The European CCMC classification includes a limit of 3.5 cP minimum for high-temperature, high-shear viscosity (HTHSV) at 150°C and 〖10〗^6 s^(-1). At the time of writing the current SAE J300 classification (revised February 1992) includes the HTHSV limits shown in Table 3. Further revisions of SAEJ300 are imminent.