It's a "visible print" typewriter, allowing the typist to see the text as it's typed. The Oliver Typewriter Company produced over a million machines between 1895 and 1928. The model in the image likely dates between 1915 and 1922. The company was later sold to British investors in 1928 and renamed British Oliver Typewriter Company. The typewriter uses a "down-strike" method where typebars come down from above to strike the ribbon.
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