UNfound:

This illustration of the Universal Letter Marker belongs to my friend, Gabe Burbano, and it is the only known image of this index typewriter. Despite how detailed the illustration is, it is not mentioned in any book, on any website nor have we found its patent. We don't known who invented it nor if there was a company set up in support of it. Not even a date is known. Again, for such a detailed illustration, one could rightfully expect more information to be available, but there is not. The Universal Letter Marker is such an intriguing mystery. (Thanks Gabe!)

Have some info about this typewriter? Have you found it? If yes, please email me at Antikey.Chop@gmail.com