IBM Selectric typewriter

The IBM Selectric typewriter was a highly successful model line of electric typewriters introduced by IBM on 31 July 1961.

Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a traditional typewriter, the Selectric had a type element (frequently called a "typeball", or more informally, a "golf ball") that rotated and pivoted to the correct position before striking. The type element could be easily changed so as to print different fonts in the same document, resurrecting a capability that had been pioneered by the Blickensderfer typewriter 60 years before. The Selectric also replaced the traditional typewriter's moving carriage with a paper roller ("platen") that stayed in position while the typeball and ribbon mechanism moved from side to side.