Loga Topo 6400A circular Surveyor slide rule in case 1950 Switzerland

This high quality metal double sided circular slide rule was produced by Loga from Switzerland. This model Topo 6400A comes with the original leather case that has kept the slide rule in good condition. It is a specific slide rule made for surveyors and army purposes for the measurement in the field and obtaining topographical information. The case is showing some signs of use or age but the leather is great and the zipper works. Inside there is a Swiss (army) stamp. It is fully functioning with good working cursor on both sides. The diameter of the slide rule is 12,5 cm or 5 inches. Check the attached video on how to work your vintage man tool : slide rule operation instructions!