Ok..so a Vitavox gp1 compression driver. This one is specially made for a certain G.W. Balkar in Julundur India. Not Jalandar

. Figured that the anglicised sounding name Balkar is actually Punjabi. But imagine a special toy coming to you from England in the mid fifties with your name embossed on it. They seem to be a business and probably spent the money to read the design, who knows.
Quickly googled to find three hits on them, G W Balkar was a partnership firm in the mid fifties that made amplifiers for the Punjab Govt, they had a motor vehicles accident claims legal case against them and there still exists by that name, a farming company manufacturing Combines.
The Electro voice looks cool and University and Jbl there too.