The Keaton Music typewriter was a typewriter specifically for music. Designed by Robert Keaton in San Francisco, California in 1933, it contained two keyboards, one moveable the other stationary, and 14 keys that plotted musical symbols onto blank paper into the carriage underneath.
The second iteration of the keyboard debuted in 1955 and sold for $225 or $2,000 in today’s value, roughly the amount it costs for a brand new Macbook Pro. Now an antique, there are no more than 24 Keaton Music typewriters left in the world.