The Starrett 300mm - 11-3/4" Combination Set with Square, Center and Reversible Protractor Head and Blade features a reversible lock bolt, scriber, spirit level in both square head and protractor head, direct reading double 180 Deg protractor scale, hardened steel, photo-engraved blade. The combination set with square includes a cast iron head with black wrinkle finish. Also available with satin chrome blade and protractor head. 300mm/11 3/4", Metric/Imperial.