The component with the lowest price in the MAGNETO schematic is the Key.
In this schematic the "Screw" is used most often.
The Cs125 1983 (d) (e1 E2 E4 E6 E15 E17 E18 E21 E22 E24 E25 E26 E39) Magneto consists of nine pieces with the Stator Assy being the most expensive.