Got this from a guy whose father & uncle were both in WW2; dad in the Navy & unc in the Army Signal Corps. My question is...Is this military (telegraph, radio, telephone) or civilian (telephone switchboard, etc)?

 

Made by "Brush Development Co", one black plastic earpiece & a metal strap with a black plastic nub at the end that has BRUSH molded in relief on it. Two wires coming from the earpiece.

They did make some military stuff but generally the military communications stuff is marked as such with part and contract numbers.

 

These look like some used by switchboard operators.