Tool Steel Plate, Appearance Metallic, Brinell Hardness 177 BHN, Heat Treatable Heat Treatable, Heat Treatment Oil-Hardened, Includes Material Certificate Material Certificate with Lot Number, Length Tolerance +0.125 in/+0.25 in, Material Tool Steel, Material Grade O1, Mechanical Finish Precision Ground, Overall Length 18 in, Overall Width 8 in, Rockwell Hardness 88 HRB, Shape Plate, Standards ASTM A681, SAE J437, System of Measurement Inch, Tensile Strength 105,000 psi, Thickness 0.5 in