The 204 is a transmitting triode. Probably of historical interest because of the manufacturer and the unusual pinout. Fil volts 11 V Fil Amps 3.05 A Plate Diss 250 W Plate V 2500 V Plate Amps 275 mA A mid-1980s price from Richardson was $860. Should make a good VTTC Happy day, Ralph Zekelman