The Stovebolt Site Forums The Shop Area The Electrical Bay Never seen this before...outside wires routed *inside* tail light bulb

I worked at a DX service station as a teen (100 years or so ago), and we rented U-Haul stuff. We did carry bulbs like this, and other pieces and parts for making fast and reliable connections to those that had no trailer lights connections installed.
The inventory came from U-Haul.
No idea if this is still a thing, or part of the past.

KC