BBI Structural Bolt, Fully Threaded Heavy, Measurement System: Imperial, 1-8 Thread, 2-1/4 in Length Under Head, Medium Carbon Steel, Plain, Material Specification: ASTM A325 Type 1, 120000 psi Tensile Strength, 24 to 35 HRC Hardness, Hex Head, 0.627 in Drive, UNC Thread, 0.627 in Head, Hex Drive, 1.022 in Shank