Frederick Post model 1468  [1925-1927]

This is the only specimen of a "Ritow Manifold Duplex" slide rule of which I am aware.    It was listed only in the 1925 and 1927 Post catalogs. 

The page shown here is from the 1927 catalog. 
For more information on Herman Ritow and Post "Ritow" slide rules, click here

These slide rules were made by Koch, Huxhold & Hanneman in Hamburg.

 Rules identifed as "adjustable" use the DRGM 192052 friction adjusting mechanism.