The HP-65 was HP's fourth handheld electronic calculator and its third scientific calculator.
Nicknamed "Superstar," the HP-65 was the first magnetic card-programmable handheld calculator, which is why some call it the "world's first handheld computer." The HP-65 could read from and write to magnetic cards, allowing the user to buy program cards from HP or save programs on cards.
Although the HP-65 was similar to the HP-35, HP's first handheld scientific calculator, new features included a card reader, the slot to hold a card below the display and the second slider switch to select program or run modes. The HP-65 cost $795 when it was introduced