Tungsram P215

Tungsram Hungary, "Barium Tube" possibly using the Azide process? Early 30's. 2 volt, 150 mA filament, maximum anode voltage 150 V. Grid bias -12 V, ra 3.3 kOhms, gm 1.5 mA/V, mu 5. Recommended load resistance 7 kOhms. B4 base. Equivalent to the Mullard PM2. The characteristics can be found at the top of this pdf file, fourth section: Triodes with resistance < 7 kΩ.