The Antique Slide Rule by KEUFFEL & ESSER CO. is a piece of historical significance dating back to June 5, 1900. Manufactured in the United States during the pre-1930 era, this slide rule is a testament to the company's craftsmanship and precision. It measures 20 1/2'' long.As a tool used in engineering and scientific calculations, it holds a special place in the world of antiques, showcasing the innovation and skilled design of its maker, KEUFFEL & ESSER CO. This is a neat one for your collection.Condition: box is missing ends, slide rule is in nice shape for being old