The product is a vintage Mac Tools 5/16″-3/8″ Bendix brake adjusting wrench, model #S43. This open-end wrench is a hard-to-find single item made in the United States. With a SAE system of measurement and a size of 5/16 inches, this wrench is a valuable addition to any automotive tool collection for those who appreciate quality craftsmanship and historical significance. Could use a good cleaning