Alloy Steel Rod, Material Alloy Steel, Material Grade 4340, Overall Length 36 in, Heat Treatable Heat Treatable, Heat Treatment Air-Hardened, Mechanical Finish Mill, Outside Diameter 5/16 in, Outside Diameter Tolerance +/-0.004 in, Yield Strength 125,000 psi, Fabrication Cold Rolled, Rockwell Hardness 100 HRC, Brinell Hardness 363 BHN, Machinability 50 Percent, Tensile Strength 186,000 psi, Includes Material Certificate Material Certificate with Lot Number, Standards AMS 6415