Interesting scales construction.
Nothing special, but easy and beautiful. IMHO.
The scales are without scale wedge.
I've never seen such construction before.
The trademark is interesting too.
Isaac Rosenbaum used trademark "Iros Keen" for about a year, 1924-25, after he opened his own import agency. Before that, he was a partner in Rosenbaum & Mogal, 1917-1924.
Isaac Rosenbaum agency located at 91 Bowery, New York City.
http://www.strazors.com/uploads/ForS...11/light_5.jpg
http://www.strazors.com/uploads/ForS...11/light_1.jpg
http://www.strazors.com/uploads/ForS...11/light_2.jpg