The Vintage Starrett No 491 4 Pc Combination Square Set is a high-quality machinist tool perfect for metalworking inspection and measurement tasks. Made of durable steel, each blade in the set has a length of 12.0 inches and features a 4R graduation style. This set includes four different pieces to help machinists accurately measure and inspect various metal components with precision. Ideal for professionals in CNC, metalworking, and manufacturing industries, this combination square set from Starrett is a reliable and essential tool for achieving precise measurements and inspections in a variety of metalworking applications.