OK. It's a revolutions counter. The bayonet type end is for a rubber end to contact a rotating shaft as required. (Aren't these ALWAYS missing, if you want to use a modern tachometer?)
I believe it would be used in conjunction with a watch, timing say a minute. The two dials then read the number of revolutions, up to 999.
It's probably about 100 years old (I haven't tried to check this), and would have been used on steam engines or similar relatively slow machines..
It is beautifully hand made. Every component has a tiny stamping of the number 18, suggesting these were made in small batches and individually hand fitted together.
True craftsmanship in my opinion. And sorry, I should have said it wasn't electrical related.