The Olivetti Summa 19: the last mechanical calculator
The Olivetti Summa 19 calculator was designed between 1969 and 1970 by Ettore Sottsass and Hans von Klier.
It was 28 by 20 by 10 centimeters tall. Its keys could input numbers up to ten digits, with results up to eleven.
Unfortunately, it was not as successful as its makers had hoped: although its innovative, streamlined design was awarded the 1970 Compasso d’Oro, it was one of the last mechanical calculators to ever be launched, in a market that by then had already completely converted to electronics.