High tempered aluminum for maximum durability. Useful tables and information stamped into square, such as: new lumber scale, decimal equivalent table, metric conversion table, formula for squaring a foundation, 45°, 60°, 30° angle markings, volume and area formulas, wood screw gauge table, nail sizes (common and finish), quantity per pound and depth scale. Deep, long-wearing graduations for easy reading. Protective lacquered coating resists corrosion.