Combination Square Number of Pieces 3 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 1/16 in 1/64 in (Quick Reading) Head Type Center/Square System of Measurement SAE Head Material Cast Iron Head Vial Included Yes Accuracy +/- .0025 in Features Reversible Lock Bolt Graduation Color Black Graduation Scale 4R Graduation Units Inches