Perfluoroelastomer (FFKM) is most commonly known by the DuPont trade name Kalrez®. Perfluoroelastomer compounds offer the widest range of chemical and solvent resistance as well as very high operating temperatures (up to 575º F / 300ºC). Food and medical grades are offered.

The price of products made from Perfluoroelastomers tend to be very high due to the raw material cost, so this polymer is used for specialty applications only. The low temperature range is only -20º to +20ºF depending on the compound. Thermal expansion needs to be considered when using Perfluoroelastomers at elevated temperatures.

P-REX™, Precision Associates' family of Perfluoroelastomer compounds are available in hardness range of 70 to 90 durometer. Black is the standard color, but white is available.