I’ve seen the FS-44 in old GE catalogs from the 1940’s and 1950’s. Has anyone here ever seen one, or at least know what they were used in? For reference, it is the same size as a T17 starter (FS-64, FS-85/850, FS-102) or the old British thermal starters, and uses the same 4 pin socket.

I also believe they made an FS-44DC for a short time in the 1950’s, designed for operation of 40w lamps on a DC supply in areas where only DC was available.