This Dietzgen Pocket Slide Rule, model No. 1556 CP, is a great addition to any collection. Measuring at 3/4 inch long, it comes with a leather case that adds to its durability and protection. Its usefulness in engineering and science is unmatched and it is sure to impress any enthusiast. This item has been previously owned but has been maintained in an excellent condition. It is perfect for collectors or for practical use. The slide rule is a timeless tool that has proved to be an essential part of any engineer or scientist's toolkit for decades. Add this to your collection today!