This Bulb(6v15/15w/stanley,a3598ha) is the most expensive of the items that make up this Head Lamp-speedometer - Tail/brake Lamp assembly.
ten components are shown in this M31 1968 Usa (e03) Head Lamp-speedometer - Tail/brake Lamp exploded diagram.
The lowest price component in this Head Lamp-speedometer - Tail/brake Lamp parts-list fiche is the Nut.