BBI Carriage Bolt, Passivated, Measurement System: Imperial, 1/2-13 Thread, 1-1/2 in Length Under Head, Stainless Steel, A2 (18-8) Grade, 1.094 in Diameter Head, 0.281 in Neck, Square Neck, 150000 psi Tensile Strength, 0.515 in Drive, UNC Thread, Square Drive, B95/C32 Hardness, Material Specification: ASTM F593, Round Head