Western Electric 300A 1950's Pair Factory Matched Tube - DKI, , Indonesia
The product is a main body (pair), a box. Western Electric 300 A It is sold with two engraved marks.
Although the year is unknown, I think that it will be the thing before 1950.
Boxes are not original but recent things come with them. When measuring with the measuring instrument TV - 7,
Both of them were  against the minimum . Both sides remain firmly in getter.