I think I just found $5 brand new preheat circline adapters! Assuming it's not just an old photo, the presence of only two wires leading to the socket suggests that these are preheat. They also sell these with /BLB circline lamps for considerably more money.

http://www.elightbulbs.com/GE-88865-FCA21-BLB-BLACK-LIGHT-CIRCLITE-BALLAST-ONLY-T9-Fluorescent

I wish I had more table lamps so I could make use of these.

I won't be surprised if it will be either a "single wire per tube end" instant start, or a "CFL-like" circuit with the resonant capacitor inside the connector.
The ballast box looks quite too small for a 0.37A choke (even a 120V/60Hz one), with the connector size I would hardly imagine to fit a glowbottle inside as well...

I thought about that, but I know GE made preheat circline adapters that looked just like this, except they were white instead of black. Even if these are electronic, it's still cool that you can buy these things. I'm guessing they won't be made much longer, if GE hasn't already shut down production.

There are not so many places, where such adapter would fit, so the demand was low.

Cool that these are still for sale, even if they are leftover stock. The circline adapters were very common in table lamps in hotels 10-15 years ago. They distributed light very evenly, unlike most new CFLs or LEDs.

I remember staying in hotels and seeing circline adapters in all the lamps. I even recall seeing incandescent bulbs in some hotels, which is unheard of now.

While I didn't really stay in many hotels, I don't recall staying in one here in Canada with circline adapters. The rooms had, except for the bathroom, all incandescent lamps until the advent of the spiral CFL... Being a lighting enthusiast, I would have remembered these adapters especially if they happened to be preheat.

The motel where I lived while going to school this year is ALL incandescent, save for a CFL here and there. Problem is they only buy cheap generic 40 watt units which are not only 130 volt, but they're rated for 6000 hours at 130 volts! So the light output equals a standard 25 watt unit. And they make no bones about using them even in a large motel room with a single ceiling light, where a 100 watt unit would be more appropriate.

I like those preheat adapters too! I have several in use, too! (GE "Circlite 75" and LOA "Lifelite") Yeah that must be DIM!