Johnson's 6” stainless steel protractor is an essential tool for students, architects, machinists, carpenters, and woodworking hobbyists for accurately marking, measuring, and transferring angles. Constructed of durable stainless steel with permanently etched, highly visible measuring scales. The protractor head has a 0° to 180° semi-circle scale reading in both directions for maximum versatility. Use the 45°, 90° and 135° reference markings for quick and precise mitre angles.