Thomas,
That is the standard end-view Burroughs Nixie tube. The two extra pins are for
activating the mercury giver, I believe.
The module appears to be European in origin. We don't have capacitors like that
in the USA, and the TI chips have a European font on their labels.
The shaft sticking out appears to turn a rotary PC board switch through a miter
gear. The switch looks like it's wired to select one of the ten cathodes.
Perhaps it allows the user to set a counter trigger value.
--
David Forbes, Tucson, AZ