A1 – Major diameter of thread.
A2 – Thread pitch
A3 – Length of threaded section.
C1 – Major diameter of thread.
C2 – Thread pitch
C3 – Length of threaded section.
E – Outside diameter of surface opposite thread A.
F – Inside diameter of surface opposite thread C.
G – Outside diameter of adapter.
H – Adapter length. The distance between the front and rear bearing surfaces.