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.
Selectrics and their descendants eventually captured 75 percent of the United States market for electric typewriters used in business.
The Selectric typewriter was introduced on 23 July 1961. Its industrial design is credited to influential American designer Eliot Noyes.
The Selectric remained unchanged until 1971 when the Selectric II was introduced. From then on practically every year a new, improved one was introduced. Business was booming.
I remember proud secretaries wearing a “type ball/golfball necklace in gold or silver.
There were also competitions, between best secretaries, The winner received a golfball necklace.