The Osram P2 is an battery audio output triode with a two Volt filament. This was probably originally branded as Osram with a stick-on paper label, but there is no maker's name visible on the glass. The centre of the plastic base cap has the letters M-OV Co. Ltd.
The electrodes are mounted at an angle within the balloon envelope.
The oxide coated filament wires can be easily seen as can the grid within the nickel anode. The latter has ribs for additional mechanical strength. Note the helical tensioning springs with hook to hold the filament.
The electrodes are supported at the top by having their wires secured within a glass rod. This is the method of construction used in the days of the Azide filament process. On the dome can be seen the Type designation of P2 etched into the glass.
The balloon envelope is 44 mm in diameter, and excluding the B4 base pins is 91 mm tall.
References: Data-sheet & 1043. Type P2 was first introduced in 1930. See also1930 adverts.
