The trackball mouse is considered one of the first computer mice and was invented and built in 1965 by Telefunken as part of a contract from German air traffic control to mark the position of aircraft on the radar. The mouse was not used there but in 1969 for Telefunken's mainframe computer, the TR440, making it the first mouse to come onto the market commercially.
Only 46 copies of the rolling ball mouse were made, but only around 8 remain. The existing copy is therefore one of the last.
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