RARE - Early CURTA Calculator TYPE II Serial : 505708 System : Curt Herzstark Made in Liechtenstein Curtas were considered the best portable calculators available until they were displaced by electronic calculators in the 1970s The Curta is a small mechanical calculator developed by Curt Herzstark. The Curta was conceived by Curt Herzstark in the 1930s in Vienna, Austria. His work on the pocket calculator stopped in 1938 when the Nazis forced him and his company to concentrate on manufacturing measuring instruments and distance gauges for the German army.Soviet forces had arrived in July, and Herzstark feared being sent to Russia, so, later that same month, he fled to Austria. He began to look for financial backers, at the same time filing continuing patents as well as several additional patents to protect his work. The Prince of Liechtenstein eventually showed interest in the manufacture of the device, and soon a newly formed company, Contina AG Mauren (aka Contina Ltd Mauren), began production in Liechtenstein. The larger Type II Curta, introduced in 1954, has eleven digits for data entry, an eight-digit revolution counter, and a fifteen-digit result counter. It weighs 13.15 ounces (373 g), based on weighing serial number 550973, produced in early 1966.