| Field | Office equipment |
| Went Obsolete | 1990 |
| Made Obsolete By | Prevalence of computer word processors |
| Knowledge Assumed | Minor hand-eye coordination |
| When useful | When using an old Selectric typewriter |
IBM introduced the Selectric typewriter in July, 1961. Unlike almost every previous typewriter, rather than a fixed bank of type bars directly connected to individual keys, the Selectric used a spherical type ball about the size of a ping-pong ball. It was mounted on a near-vertical shaft on a moving carriage, and pressing a key caused a system of clutches to both spin and tilt the ball to the correct angle to press the needed character against the ribbon and then onto the paper.
The balls were replaceable, so that any of dozens of typefaces could be used, though most Selectrics left the factory with the same typeface they would use for their entire lives. To remove the ball, a lever on top of the ball was flipped into the vertical position, freeing a clamping mechanism inside the ball that held it to the shaft. The ball could then be picked up off the shaft and another ball put in its place. Replacing a ball took perhaps five seconds and could be done in the middle of a document, allowing the typist to use different typefaces on a page at the same time.
The ribbons for Selectrics were in a cartridge form. Replacing them involved flipping up a large cover over the mechanism, and releasing a latch to one side of the ribbon cartridge. A new cartridge could then be put in place, the latch secured, and the cover flipped back down. Replacing a ribbon took less than 30 seconds.
The earliest Selectrics in 1961 had to be specifically ordered according to the ribbons the user intended to use. A machine had to be ordered to use cloth ribbons or carbon-film ribbons, and they could not be interchanged. The design was changed soon after so that any Selectric could use either cloth or carbon-film. Later Selectrics had a correcting feature that involved a “correction ribbon” which was able to lift carbon-film printing off the page or overprint cloth impressions with a dry white-out-like substance. Changing the correction tape was a more involved process as these tapes were reel-to-reel type.