This is a high impedance Triode used by VLQ9 Bald hills Queensland. It has a Tungsten filament run at constant amperage. The Copper tube is the Anode which is immersed in a thimble thru which flows distilled water to cool the anode. The Anode operated at a potential of about 12kV. Despite the long leads and interelectrode capacitances, the valve could be operated at HF shortwave frequencies below about 25MHz, running Class C with Amplitude Modulation.