The 4890B compound is an explosive decompression resistant perfluoroelastomer. It has been designed specifically to meet the challenging demands of oil and gas applications that require the chemical resistance of perfluoroelastomers together with high explosive decompression resistance. 4890B has been tested according to NORSOK M710 and passed at the highest possible rating of ‘‘0000’’. Its fully fluorinated backbone structure provides very broad chemical and thermal stability. It has a low compression set, excellent chemical resistance, good mechanical properties and outstanding thermal stability.