Prototype of HP's first calculator watch can be yours for $14,500
Compuchron Calculator Watch
Hewlett-Packard HP-01 calculator watch-NEVER WORN in original box-Vintage 1977 14k gf Men's Calculator Watch - Etsy Portugal
Hewlett Packard HP-01 LED Gold Tone Calculator Watch--WORKS! NO RESERVE! | WatchUSeek Watch Forums
1977: The HP-01 calculator watch can calculate dynamically using time as an argument. The user can watch as the cost of their international call increases on the display. : r/RetroFuturism
HP-01 - Wikipedia
Hewlett-Packard's Watches - Hewlett-Packard History
Historical Perspectives: Meet The Very First Smartwatch: Behold The HP-01, from Hewlett-Packard - Hodinkee