Max:
Take a look at the linked message below...it discusses these lights and has another link to a photo of
an original vintage light (probably made by Kaco).
Also a links to a website that was selling a similar modern light painted black.
http://www.sl113.org/forums/index.php?topic=16574.0These lights were made by Bosch and Kaco. The vintage lights I've seen (and owned)
were unpainted, had a round grey cord about 20 or 25 feet long. They have a clip to
allow attaching the lamp to a nearby spot to allow hand free use.
The bulbs are still available...change the bulb to modify from 6 to 12 volt if necessary.
There are other lights around that seem identical except they were made to fit the cigar lighter socket not the underhood socket.
These lights were used in several other German marques at the time including BMW.
They were also used for BMW motorcycles but with a shorter cord.
Originals come up on eBay from time to time at fairy high prices sometimes approaching or surpassing $200.
Richard M, NYC
Use the Search here and look for "kaco" for more info.