Mike,
They were originally designed and marketed by
Ashaway Line & Twine of Rhode Island & New Jersey and manufactured from the late 40's, i.e. 47-48, through the early/mid 50's. There are 2 models, the Slip Cast, and the larger Surf Cast which has a black body. The reel is basically stainless steel, except for the spool, which is aluminum.
Ashaway contracted with Ohio Tool Co to manufacture the reels and Ohio Tool manufactured some reels with their Ohio Tool name stamped on them. Both companies' reels are identical and parts will interchange.Values are also the same for comparable models from both companies with the Surf Caster usually bringing a little more. The reel sits on top of the rod rather than under so a casting rod is feasible. The lever is used to hold/retain the line with your thumb while casting. Open the bail, retain the line by pressing down on the thumb lever and cast like a spin casting reel. The line then free flows out just like an open face spinning reel. Crank and the bail closes to wind in line. I think they are an awkward contraption to try to cast but their design was in the early US spinning days and you didn't have to also buy a spinning rod to use them. I suppose on could get proficient after a while but I don't have the patience.

Pyramid Manufacturing Co of Cleveland, Ohio produced a reel similar to the Slip Cast for a couple of years in the 50's after OTCO stopped production. The Pyramid reel is harder to come by and generally brings at least twice the price.
FYI, if you'd like to get the Tell All Spinning Reel Bible, i.e. "Wright's Spinning Reel Reference & Value Guide", PM Ben Wright (Ben) and he will set you up with the best multi inclusive open face spinning reel reference ever printed.
Tom