This part of ISO 6194 describes seals utilizing elastomeric sealing elements. They are normally considered suitable for use only at low pressures (see ISO 6194-1:2007, 6.1). This part of ISO 6194 defines and classifies typical surface imperfections that can impair the function of the seals and is intended as a convenience for purchasers and manufacturers in their discussions concerning the importance of these imperfections in different applications. NOTE ISO 6194 (all parts) is complementary to ISO 16589 (all parts), which covers seals incorporating thermoplastic sealing elements.