Unveiled in 1977, the Hewlett Packard HP-01 “was unique due to these unique features: Datatype for time, date, and time interval, and the ability to perform mathematics on these datatypes.” Auction page. Click here for first picture in gallery.
The HP-01 used light-emitting diodes (LEDs) for its digital display. Introduced in 1977 at the height of the LED watch craze, two models were available, a gold filled model for US$750 and a stainless model for US$650.
