Vintage K&E Slide Rule Manual Log Log Duplex Decitrig No 4081 Keuffel & Esser Co Vintage Keuffel & Esser Co. slide rule manual for the Log Log Duplex Decitrig No. 4081. It provides comprehensive instructions and diagrams for operating the front and reverse faces of this professional-grade mathematical instrument. A significant piece of mid-century engineering history, perfect for collectors of scientific instruments or vintage technical literature. Measurements: • Height: 8.5" • Width: 5.5" Book is clean and in very good condition. Please see photos for full details. Thanks for looking! - From a smoke and pet free home. - Item shown is the exact item you will receive. We always carefully package and box ship ASAP. ***Be sure the FOLLOW us, We post items often and offer discounts when you bundle. ***Ships from Idaho*** #Casual