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Details and Image



Item#TypeModel No.Match No.Variant No.Model NameMakerCountryProduction or Serial No.MaterialScale LengthDateCondition
KEU281Linear
Mystery
Unknown
n/a
Mystery PolyphaseKeuffel & EsserUSA
687519
Engine divided celluloid laminated mahogany
"20"
1940
C7

Notes: "Mystery 20" sliderule with scales: K DF [ CF CI C ] D A on front and [ S B T ] on reverse of slide. USBS Circular 47 version of conversion table."

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