This curious headset from the past is an exhibit in the Museum-Study of Bruno Pontecorvo at DLNP. We assume that this device was intended for delegates of international conferences in order to listen to simultaneous interpretation.

There are no identification marks which could tell us something about the device manufacturer, no quality label and no GOST number. Even no regular price, for instance, 3 rubles 07 kopeks.
These headphones might have been assembled at one of Institute workshops. The highest qualification of ”blue collars” working at JINR allowed them to make a device of this kind on their own, which was of relevance in that epoch of deficiency.
If you know for sure what kind of device it is, where it was manufactured and what it was used for,This email address is being protected from spambots. You need JavaScript enabled to view it.!
In the photo: Headphones from the Museum-Study of Bruno Pontecorvo (DLNP, JINR) (from the JINR Photo Archive)… 

Общий вид зала заседаний. На переднем плане советская делегация во главе с В. П. Джелеповым. (Репродукция из ЦГАКФД) | Перевалов Г., ОИЯИВ зале заседаний | Туманов Ю., ОИЯИ