IWA 0796 vacuum calculator circular slide rule 1969 Germany

This is an IWA made double sided circular slide rule with a cursor on both sides with number IWA 0796. It was made for the Leybold-Heraeus company in 1969. This company still produces vacuum pumps and other components for vacuum plants, laboratory and scientific research. It is used for calculating volume, pressure, pumping time and effective pumping speed. The manual is printed inside the paper sleeve in English, German and French. The slide rule itself is made of 2 plastic discs and a plastic wrap over cursor, all in very good condition with minimal signs of use, it measures 13,5 cm or 5 1/2 inches in diameter. Check the attached video on how to work your vintage man tool : slide rule operation instructions!