Kellogg 402
AC Det/Amp Triode
~1927

The 402 has a 3 volt, 1 amp filament like the 401. Testing of several working samples yielded results similar to the 401, and the distinction between the 401 and the 402 is not known. This tube is not an output tube like the 403 (1.5 amp filament) despite published data to that effect. This tube was also made with an engraved base and no marking on the bulb.