Combination Set, Number of Pieces 4, Blade Finish Brushed, Blade Material Steel, Head Length 4 1/2 in, Head Width 3/4 in, Blade Length 12 in, Blade Thickness 0.09 in, Blade Width 1 in, Graduation Mark Style Etched, Graduation Marks - Front 1/100 in (Aircraft Quick Reading), 1/64 in (Quick Reading), Head Type Center/Reversible Protractor/Square, System of Measurement SAE, Head Material Cast Iron, Includes Blade, Non-Reversible Protractor Head, Head Vial Included Yes, Accuracy +/- .0025 in