This K & E Slide Rule 4181-3 is a vintage collectible from the United States, featuring a leather sheath and copyright information from 1947. It is perfect for engineering and science enthusiasts, as well as collectors of vintage items. The slide rule is made by Keuffel & Esser, a renowned brand in the industry. This item is a must-have for anyone looking to add a unique and valuable piece to their collection. 12 inches long.