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Details and Image



Item#TypeModel No.Match No.Variant No.Model NameMakerCountryProduction or Serial No.MaterialScale LengthDateCondition
KEU640Linear
Mystery
Unknown
n/a
Mystery Duplex (Filter Dept.)Keuffel & EsserUSA
5304
Engine divided celluloid laminated mahogany
"20"
1945
C5

Notes: "Special order/design slide rule made for making filter calculations, possibly for electronic filters or mechanical filters.  The slide rule was probably used for designing the filters based on parameters using the R, SI, TI1, and TI2 scales. Has a DIF scale which I have never seen on a K&E slide rule."

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