Keuffel Esser 4181-1 Duplex DeciTrig pocket slide rule case 1960 USA

This is a quality build pocket slide rule with elaborate calculation options through 21 different scales. This great rule also come in the original signed dark green leather case with belt hook (some scuffs on the back where a name used to be). This K+E rule is in good condition, with only signs of normal use. It is made entirely of Ivoride plastic with metal ends and partial metal cursor. This pocket 4181-1 model Duplex Decitrig measures 18 cm or 7 1/4 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!