The speedometer cable is secured in the hub cap with a cotter pin or locking ring. The model years given are those used by Volkswagen at the time. If no year of manufacture is indicated, they were used interchangeably.
If there is a hole in the cable, use the cotter pin listed here. If there is a groove in it, you must use the locking clip (see tab "other models"). If both are present, then you can choose, as both locking systems are then applicable.
On the Bay Window Bus, it was never used at the factory for the speedometer cable but applied for securing the brake pressure rod.
Useful information from Paruzzi magazine and from our YouTube channel :
Look for more technical articles on the page Paruzzi Magazine