The LG210 is a dull emitter triode for use as a detector of AF amplifier.It was made in Hungary by Tungsram and the box clearly states that it is a Barium Valve - Tungsram's name for the Azide process.
It is difficult to see the electrodes because of the blackening of the envelope either side of the box anode opening. This blackening is a result of the Azide process that produces the emissive surface on the filament. The 'V' filament is surrounded by a bright wire flat oval shaped grid. The anode is mounted at 45 °.
The identification is etched into the dome of the envelope.
The balloon envelope is 47 mm in diameter and, excluding the B4 base pins, is 87 mm tall.
References: Data-sheet & 1043. Type LG210 was first introduced in 1930. See also1930 adverts.
