The PGK is a bidirectional seal and composed of two elements. The dynamic seal is a ring in TRIAMIDE® (Glass Filled Polyamide) while the static seal is a TRIAFLEX® (Square Ring) also acting as energizer. The Cut on the seal prevents the seal failure in case of a ballooning or expansion of the Cylinder and it is so designed that the oil does not move from the pressurized chamber to the other. Depending on the application, media, cycle speed etc., the Polyamide compound is selected and the Square Ring compound is selected considering the media compatibility, temperature etc.