TOP SEALING EPDM PTFE ENVELOPE GASKET STYLE 7700 EPDM PTFE Gasket is made of teflon for high temperature resistance, high strength.It is made by 100% Virgin PTFE with bonded with EPDM RubberThis can be avaliable for enough pressure. EPDM PTFE flange gasket has EPDM's advantage and also PTFE's advantage. Gasket has two sealing rings a primary and secondary. Almost universal chemical resistance and non-contaminating for ultra-oure applications, along with the EPDM memory giving a long sealing life.