Parts such as the Gasket Kit A: Gasket,cyln.head (nas), Oring,33.5x3, O Ring,13x2.5, Packing,breaker (mca) are included in the Atc200s 1984 (e) Usa Gasket Kit A parts fiche.
The Gasket Kit A is made up of components including this Gasket Kit A (as) (mca) which is the most expensive.
In this schematic the "Seal,valve Stem" is used most often.