The AC/VM is a vari-μ screen grid valve or tetrode. It is indirectly heated and features the UK standard heater rating of four Volts at one Amp.
WE have not yet found details of Europa valves but clearly they were not made in the UK as the word Foreign indicates.
The screw top cap places this as being made in the early 1930s.
The reverse is plain metal loaded paint that is showing considerable corrosion.
The balloon envelope is 47 mm in diameter, and excluding the B5 base pins is 111 mm tall.
Absolute Maximum Operating Conditions¶
Updated February 27, 2019. shape:balloon construction:pinch type:tetrode age:1930.1940 base:b5 heater:4.0v pins:5 pin:1.g1 pin:2.g2 pin:3.h pin:4.h pin:5.k.s pin:tc.a