6-inch Extra Fine Slide Rule
Frederick Post model 1453 [1936-40]
Hughes Owens model 1764
Hemmi model 54
Top edge: 0-6 inches (Slanted)
Bottom edge: 0-1-17.5 cm (Vertical)
Back of slide:[S, L, T]
Back of rule: 

This page is from the 1936 (18th Edition) Post Catalog 
The term "Universal" is new and seems to be Post's term for its best products.

 Catalog describes this rules as "5-inch" but scales are actually 15 cm (6 inches) long