The DC2/200 is a full wave high voltage vacuum rectifier. The base has just two pins that connect to the filament wire.
The twin anode boxes. The anodes connect to the two screw top caps and within the anode looks to be a M shaped wire filament - probably of thoriated tungsten.
The lower filament supports enter the anode. The structure is secured with a collar around the pinch and the four anode supports are separated from the collar by glass rods.
A clearer view of the lower components. The filament can just be seen inside the box anodes. On test no heating was seen with the rated filament parameters. At four volts the filament glowed dimly at just over four amps. At 6.3 Volts the current is just under five amps and the filament runs at thoriated tungsten orange.
With a little enhancement the filament wire is better seen. The wire looks to be coiled and there is no sign of an oxide coating - as one would expect with rated voltage. The Made in Holland also becomes easier to read.
The balloon envelope is 72 mm in diameter, and excluding the base pins is 160 mm tall.
Reference: Datasheet. Type DC2/200 was first introduced in 1932.