Vintage/ Rare Aristo "Praktiker" cheapest Slide Rule, #945.

cheapest Rare Vintage Aristo "Praktiker" , #945 Slide Rule. Made in Germany in the 1950s. Original cloth laminated box in used, but good condition. Slide rule is in excellent condition, slide bar moves freely, cursor window is clear, without scratches and also moves freely. All numbers and gradients are fully legible. Standard rule on back to 11 inches. The condition of this rule and the original box make it a rare find.