The Starrett 6" Combination Square with Square Head includes a reversible lock bolt, scriber, spirit level (except 4"), and hardened steel, photo-engraved blade with regular or satin chrome finish. The combination square includes a cast iron head with a black wrinkle finish. 6", 4R Grad, Satin Chrome Blade. The square head has a precision ground 90° square face and a 45° miter face. It is a highly versatile layout tool for scribing right angles and parallel lines, and a measuring tool that can be used as a tri-square, miter, depth gage, height gage, and level. Starrett precision measuring tools have been the standard for high-quality dimensional measuring tools since 1880. The powerful tools meet or exceed the accuracy and performance requirements of national and international standards, and are traceable to the United States National Institute of Standards and Technology. The L.S. Starrett Company, founded in 1880, manufactures more than 5,000 variations of Precision Tools, Gages, Measuring Instruments, and Saw Blades for industrial, professional, and consumer markets worldwide.