FEP encapsulated O-ring can resist the erosion of almost all the chemicals. It can be used in a wider range of temperature with good compression property, friction-resistance, seal endurance and longer sealing life. It is mainly used in pump, valve, reactor, mechanical seal filter, pressure container, heat-exchange container, boiler, flange, gas compression motor etc.. Reference: At present, we can offer FEP encapsulated (transparent pipe of tetrafluoroethy-lene-hexafluoropropylene with the temperature range from -200℃ up to 220℃) and PFA encapsulated(transparent pipe of PolyFluoroAlkoxy with the temperature range -200～255℃) The materials inside are Silicone and FKM.