This round slider rule is marked Aristo 622 and comes in it’s original leather signed sleeve and with it’s manual in German (marked 1961). Made for easy and simple calculating using the scales from the inside out 1/x, x, x, x2 and x3. Fully functioning with complete cursor and in good condition, only small signs of use or age (some darkening to the yellow). Original leather pouch is marked “SICHER ARBEITEN mit der Maschinenbau – und Kleineisenindustrie-Berufsgenossenschaft”. Diameter of the disk is ca. 12,5 cm or 5 inches. Check the below video on how to work your vintage man tool : slide rule operation instructions!
