10-inch Electrical Slide Rule
Frederick Post model 1456 [1936-40]
Hughes Owens model 1770
Hemmi model 80
This page is from the 1936 (18th Edition) Post Catalog.
There were many variants of Hemmi model 80; no doubt there are a lot of variants of Post model 1546. This specimen has over-range extensions that are not shown in the catalog.