Federal Tel & Radio 7C23 vacuum tube
 

I came across a very large 7C23 vacuum tube and know nothing about it.
Could anyone let me know what the specs are on this thing? It's got a
wiring connections guide printed on the side of the heat sink but it's
rubbed off over the years and I can't read it. Does anyone know how to
wire this thing? Any other help you could give on it is appreciated.

Thanks,
-Mark Dickinson