IWA 0678 flow slide rule for Gulde Regelarmaturen 1970 Germany

This is a very specific slide rule chart for calculating gas and liquid flow through various conduits. Even the cursor has a small diagram on it. On one side there is also a slide chard half. The double sliders are a great extra feature as well. It was produced by IWA, designation 06.78 from Germany for the Gulde Regelarmaturen company, ca. 1970. It has a very sturdy build with a black frame and 2 separated cursors (one on both sides) that move within that frame. Probably to create a slide rule with extra water resistance. It is in complete and working with small signs of use and age. No sleeve. It measures ca. 32 cm or ca. 13 inches long. Check the attached video on how to work your vintage man tool : slide rule operation instructions!