Are those glass "probes" solid ... or are they filled with something?
I can't quite make out what the controls legends are.
What are we talking about here? Mains voltage?
And what does that middle control say:- Pulse (or Peak?) and Stream?
I guess that the extra-safe (?) bayonet lamp connection indicates "home use" (as in:- "don't try this at home folks")!
A Collectors' Item? Best get it on eBay, then!