Hex Bolt, Partially Threaded, Measurement System: Metric, M20x2.5 Thread, 300 mm Length Under Head, 8.80 Grade, Medium Carbon Steel, Zinc Blue CR+3, UNC Thread, 12.715 mm H Head, Hex Head, 830 N/sq-mm Tensile Strength, 20 mm Shank, 23 to 34 HRC Hardness