20-inch Electrical Duplex Slide Rule
Frederick Post model 1460 [1936-40]

Hemmi model 154

No brand name (not Post or Hemmi) on rule but "Frederick Post Co" on case.  (Hemmi trademark on cursors.)  Rule has two cursors.  Both cursors have etched scale labels in red.  Hemmi put scale cursor labels on 20" rules for a short period before WWII.  (1939-40?)  Most of the cursor scale labels were green; these red cursors are unusual. 

This page is from the 1936 (18th Edition) Post Catalog.