In this schematic the "O-ring,61x2" is used most often.
A sample from the products for the E-4 Clinder include: Cylinder Comp., Gasket,cylinder (mca), Bolt,flange, 6x32, Dowel,pin,10x16.
The E-4 Clinder assembly is constructed from several parts from which the Cylinder Comp. is the most expensive.