ok, yeah, i know the picture's too big. cope.
One gets the impression that concise only made circular slide rules; their manual seems to imply this. Also, while this rule was made by Concise alone, they seem to have been purchased by Sama & Etani at some point prior to producing my Model 600. So what, you say? i'm not sure myself. Anyway, nice little slide rule, huh? Unlike the 600, this one has a fairly limited set of cheats on the back, mostly conversion factors. It's also got fewer scales (it lacks the trig and L scales). What it does have is a lovely advertisement on the case for Frank Samuel & Co., purveyors of fine ceramic raw materials to the greater King Of Prussia, PA area.