Very early compactron
 

You can find anything on e..y:

http://cgi.ebay.com/ws/eBayISAPI.dll...%3D3%26ps%3D20

According to my Sylvania tube manual, it's simply a triode tube with a loktal base for use in battery radios. Nothing special.

I was referring to the fact that the seller called it a 'compactron'...
Sorry the joke fell flat. Good night.

In a way it is. Seaford's near me kinda...maybe this fellow has other stuff.

I was thinking, when I saw the article title before looking at it, it might have been one of those multi-function tubes made in Europe before WW2. Some of those had resistors and caps inside the glass envelope. Something about a tax assessed on the number of tubes in a radio, they counted a single glass envelope as one tube, even if it had a diode, 2 triodes and a pentode inside the single glass envelope.