This classification system tabulates the properties of thermoplastic elastomers (TPEs) that are intended for, but not limited to, use in automotive applications. This classification system is based on the premise that the properties of TPEs can be arranged into characteristic material designations. These designations are determined by type, based on resistance to heat aging; and class, based on resistance to volume change resulting from oil immersion. Basic levels are thus established which, together with values describing additional requirements, permit complete description of the properties of all TPEs. In all cases where provisions of this classification system would conflict with those of the detailed specifications for a particular product, the latter shall take precedence. This classification is based on SI units.