PTFE Envelope Gasket consists of asbestos, non-asbestos, rubber etc.，Cushion material having exposed surface covers with PTFE envelope. Depends on excellent corrosion resistance and compression resilience, it is widely used in strong alkalis, cryogenic fluids, oxygen, chlorine gas and disallowable polluted medium etc. PTFE envelope gasket is used to seal pipe flanges glass lined, PVC or FRP. Low bolt torque effecting a seal and chemical compatibility are main characteristics of this type of gasket.