10-inch Universal Slide Rule with Folded Scales
Frederick Post model 1455 [1936-40]

Hemmi model 50/1p
Top edge: 0-10 inches (Slant) 
Bottom edge: 0-28 cm (Vertical)
Back of slide: [S, S&T, T]
Back of rule: THE FREDERICK POST CO.  NO. 1455, Table on plastic.

This page is from the 1936 (18th Edition) Post Catalog.  Post used the term "Universal" for many of their better quality products. 


The catalog scales are different from the specimen rule scales. 
The catalog shows  // A, DF [CF, CI, C] D, K   &   [S, L, T] ||.    If you have a specimen with the same scales as the catalog please let me know.