High quality Pocket slide rule by the German company Aristo. This is the model 803 from the 1970’s. It comes as a complete set in the original leather signed sleeve with box and manual. It measures ca. 16 cm or 6 1/4 inches long. The slide rule and the slider are made of plastic, manual is in Dutch. Everything is in good condition with hardly any signs of use and age, except the box that has tape on both sides. Check the attached video on how to work your vintage man tool : slide rule operation instructions!