ISO 16589 specifies seals utilizing sealing elements manufactured from suitably formulated compounds based on thermoplastic materials, such as polytetrafluoroethylene (PTFE). They are considered suitable for use under low pressure conditions. This part of ISO 16589 shows seal types and examples. It also specifies the nominal dimensions and tolerance of the seals, shafts and housings, as well as a dimensional identification code. NOTE ISO 16589 is complementary to ISO 6194, which covers seals incorporating elastomeric sealing elements.