The Marconi P2 is an battery audio output triode with a two Volt filament made by M-OV. The Marconi brand is etched into the side of the envelope.
See alsoP2 a later version with a shouldered envelope and vertical electrodes.
The electrodes of this triode are placed diagonally in the envelope.
The gettering makes a clear view of the triode difficult. The filament is a pair of inverted V's and the tension springs can be seen at the top right of the picture.
The balloon envelope is 44 mm in diameter, and excluding the B4 base pins is 93 mm tall.
References: Data-sheet & 1043. Type P2 was first introduced in 1930. See also1930 adverts.
