DeForest CF2160
DC RF Amplifier Triode
~1924

The DF CF2160 was advertised by a surplus dealer in 1932 and listed as a Navy "Short wave receiving type". CF2160 is etched in the glass and the filament draws .8 amps at 2 volts. The internal structure is similar to the DV-3, but has a larger plate that appears to be tantalum or molybdenum.