20-Inch Mannheim Multiphase Slide Rule
Frederick Post model 1454 [1925-30]
 
No specimens known.

The 1925, 1927 and 1930 Frederick Post Catalogs all had this identical page.

This rule was made by Koch, Huxhold & Hannemann.

Rules described as "adjustable" use the DRGM 192052 friction adjusting mechanism