The StudioLog 0969 and 0869 were produced in Germany from the late 1960's until probably 1977. Fabricated with high grade PVC (Astralon/Aristopal), plastic braces, and all plastic cursor with four gauge lines for quick HP-KW conversion. The 0969 is the widest All Purpose slide rule I have seen, with 2.75 inches width and 14 inches long. It has 29 scales that place it in the group of most powerful (and beautiful) slide rules ever fabricated. The 0869 is the pocket version of the 0969, with all same scales and configuration.
This "massive" slide rule (I have to confess that I was impressed the first time I handled a 0969: 2 5/8 inches = 6.7 cm by 14 inches = 35.56 cm) is well suited for science and engineering applications, the 0969 and 0869 have the scales: LL00, LL01, LL02, LL03, A [ B, BI, K, L, CI, C ] D, LL3, LL2, LL1, LL0 on the front face, and ST ST, T1, T2, DF [ CF, CIF, S, CI, C ] D, DI, P, S Cos on the back face.
According with the engraved serial numbers on the 0969 specimen shown below, this was fabricated in 1969 in Hamburg:
According with the engraved serial numbers on the 0869 specimen shown below, this was fabricated in 1972 also in Hamburg
Here is a link to a virtual emulator of the 0969:
The next problems can be solved with a precision of two-three decimals using the 0969:
Here is a scan made by Greg Scott of the 0969 user manual:
I'm including this scan of the 1955 Aristo Products Catalog shared by Murray Felstead, a friend of the Slide Rule Fan Club in Facebook
References:
Mosand John: A Brief History of the Aristo Studio Slide Rule. http://www.oughtred.org/jos/Mosand_BriefHistoryOfTheAristoStudioSlideRule.pdf
Aristo: Product Catalog 1969: https://drive.google.com/file/d/1il3ty5j3n2rC4mHHBqag1jX788X1EmNd/view?usp=sharing
Aristo-Werke, Denert & Pappe KG: 100 Years of Aristo Slide Rules 1872-1972, Hamburg. 1972. https://drive.google.com/file/d/1AYMhF20TCHU_nUQLkx0RaJ9pNK1vTyic/view?usp=sharing
Smith Hughes, Richard: Watch your Ps and Qs -The Pythagorean Scales- Are They Worth the Effort? Journal of the Oughtred Society, Vol 15, No.2, 2006. https://osgalleries.org/journal/pdf_files/15.2/V15.2P50.pdf