HP 80

HP80 was the first business calculator from HP.  Display uses scientific notation, 10 digits mantissa, 2 digits exponent, red LED.  Has functions for business and finance calculations, such as compound interest.

3.6v (3x AA rechargeable cells in a battery pack).

80 x 149 x 36 mm (3.2" x 5.9" x 1.4").

Launched in February 1973, the HP-80 was HP's second handheld electronic calculator and its first business model.