Fowler's 'Magnum' long scale calculator - MAAS Collection
Fowler
Fowler's Long Scale Calculator Circular Slide Rule | National Museum of American History
c1920 Cased Fowler's Long Scale Circular Calculator : Parade Antiques Online Shop UK | Plymouth, Devon, All our finest items available to purchase worldwide
Fowler "Jubilee Magnum" Extra Long Scale Calculator. - Gilai Collectibles