Raytheon CK-1006 plate-voltage full-wave gas rectifier
Raytheon has a long history in gas-filled rectifiers. This type, probably the most frequent type, can be used for voltages up to 600 V at 200 mA (600 mA peak). Filament rating is 1.75 V at 2 A. System voltage drop is about 12-15 V.

Although this tube can be used without external heating - the arc igniting even with cold cathode and providing enough heat to get sufficient emission - I recommend using it only WITH (pre)heated cathode. Cold ignition is quite a rough process, the arc often blasts white glowing oxide particles off the cathode. In unheated operation, the arc forms a very hot, sometimes flickering emissive spot wandering over the surface of the cathode. With heated filament, emission is very even and constant over the whole surface.
 
This type has an inert gas filling - I assume Argon or Crypton - which shows a nice purple ion cloud around the filament and in the two anode cylinders. Anodes are small Graphite sticks enclosed in ceramic cylinders (the two white tubes) to increase maximum reverse voltage. Spiralled oxide-coated tungsten filament is visible in front of them. It also had a "smaller brother", the 1007, which had its small glass bulb within a steel cover, so it looked just like a "true" metal tube. It was mainly used in old car radios.
For other pecularities and safety hints in operation of gaseous rectifiers, please see also page 83.htm.

Here are two pics of this tube in my amp (4x EL 36 power tubes) in operation:
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