This round slider rule is marked ALRO Syst 200R, comes in it’s complete metal case and a vintage hand made black sleeve. Made in Holland in The Hague during WWII. It does not have the standard aluminum case but the much heavier lead case, due to material shortage. These were also made with a bad cursor that Alro promised to replace for free after the war. This is probably why an extra cursor hairline is drawn on it. It is in good working condition with only small signs of use and age. Seems it has been treasured or little used due to circumstances. Closed it measures ca 13,5 cm or 5 3/8 inches wide. See pictures for details.
Check the video on how to work your vintage man tool : slide rule operation instructions!
