Type A - without gasket
Type AC - with gasket in copper
Type AA - with gasket in aluminium
DIN908 Threaded Plug
The gaskets in types AC and AA correspond to the gaskets DIN 7603, type A (flat gaskets), and are available in aluminium or copper.
Steel ST, Tensile strength class 5.8 (500 N/mm), ultrasonically and tensile tested, zinc plated, nano-passivated (silver / yellowish)