BBI Square Head Bolt, Fully Threaded, Measurement System: Imperial, 1/2-13 Thread, 1-1/2 in Length Under Head, A Grade, Carbon Steel, Plain, Square Head, 0.348 in H x 0.75 in W Head, Material Specification: ASTM A307, UNC Thread, 1-1/4 in Thread Length, Square Drive, 0.348 in H x 0.75 in W Drive, 60000 psi Tensile Strength