Keuffel & Esser Slide Rule Mens OS Cream Fair Log Log Duplex Decitrig N4081-3 Vintage Keuffel & Esser Log Log Duplex Decitrig slide rule remains a classic piece of engineering history, featuring a comprehensive array of scales including LL02, LL03, DF, CF, CIF, CI, C, D, LL3, and LL2. This 1947 copyright model, numbered N4081-3, is constructed with the precision craftsmanship expected from a Made in U.S.A. instrument. It comes housed in its original brown leather carrying case, which shows significant wear and patina consistent with its age and professional use. The slide rule itself displays some surface aging and personalized markings ("A.L.S.") on the metal end pieces, adding to its authentic mid-century character. Brand: Keuffel & Esser Model: Log Log Duplex Decitrig N4081-3 Material: Synthetic, Metal, Leather Year: 1947 Origin: Made in USA Engineering, Mathematics, Mid Century, Scientific, Analog Computing Please see all photos for more on the description #Utility