Unknown Powerstat

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Yurtle Turtle <yurtle_t-at-yahoo-dot-com> 

I just picked up a pair of ganged Powerstats at a
garage sale. They weigh in at around 42 pounds for the
two of them. They have no markings other that on the
bottom, where each one says GP58004. Does anyone know
how to identify the voltage or amperage of the thing?
I'm guessing it's a 120v 15a, but how would I know if
it's a 240v?

Pictures are at:

http://www.hot-streamer-dot-com/adam/garage/variac1.jpg

and

http://www.hot-streamer-dot-com/adam/garage/variac2.jpg

thanks
Adam

_