The Starrett No. 435-12-4R combination square set is a high-quality tool used in metalworking for precise measurements. Made of steel and crafted in the United States, this set includes a center square, protractor, and scale. The 12-inch blade length and 4R graduation style make it ideal for accurate inspections and measurements in various industrial applications. This combination square set from Starrett is a reliable and durable option for professionals in the field of CNC machining and metal manufacturing.