This compact cylindrical handheld calculating machine has black metal sides, a plastic top, and an operating handle. Eight slots along the side of the cylinder hold levers that are pulled down to set numbers. The digit entered appears at the top of the slot. Holes around the top edge reveal the multiplier digits, which may be up to six digits large. The result also shows through holes around the edge of the top and maybe 11 digits large. The top may be rotated, as one would move a carriage on an earlier stepped drum calculating machine. Sliding decimal markers indicate decimal places in entries, multipliers, and results.

To zero the machine, one raises the carriage and rotates a black disc under the operating lever through one turn. The operating handle is pulled out for subtraction and division. A lever on the side of the cylinder may be set for subtraction rather than addition in the revolution counting register.

The machine fits in black metal cylindrical case. The lid of the case turns clockwise to open.

A mark on the side reads: CURTA. A mark on the base reads: System Curt Herzstark (/) Made in Liechtenstein (/) by Contina AG Mauren (/) Type I No 61644. A mark on the lid reads: OPEN.

The Curta calculating machine was invented by the Austrian Curt Hertzstark (1902–1988). Hertstark, a Jew, was subject to imprisonment by the Nazis when they captured Austria. He worked on the design of the Curta during World War II as a prisoner at the concentration camp of Buchenwald, and produced the machine after the war in Liechtenstein. The Curta Type I was sold from at least 1949 until early 1972, when handheld electronic calculators replaced it.