Smiths Woven Fabric circular slide rule full set ICI 1970 England

This quality and rather unique round slide rule is called the Woven Fabric slide rules and was constructed by Smiths (Calculators) Ltd from England for the ICI Company. It is based on the “TERLYENE filament Yarn for Apperal uses” from 1968 and was used for rapid calculations for the design and manufacture of woven fabrics. On the back is also a Yarn count conversion slide rule for  different systems known at that time. The original manual explains all in English. It als comes with the original sleeve. The black scales are static where the red scales can be set with use of the blue markings in the cursor. It is heavily constructed and in great condition, it measures ca 14 cm or 5 3/4 inches in diameter. Check the attached video on how to work your vintage man tool : slide rule operation instructions!