Chemraz and Kalrez are members of the perfluoroelastomer family. Polymer chemists describe the base (raw) perfluoroelastomers as polymers of three or more monomers in which all hydrogen positions have been replaced with fluorine. The outstanding resistance of perfluoroelastomer vulcanizates to heat and most chemicals and solvents is the result of this state of complete fluorination. The principal monomer of both Chemraz and Kalrez is tetrafluoroethylene (TFE). The effective temperature range for Kalrez is +5ºF to + 600ºF, for Chemraz –20ºF to +450ºF. A white Chemraz compound is available and features less impurities and less electrical conductivity.