Hex Head Bolt 1/2″ – 13 x 3-1/4″ Long Grade 8 ” 4 Bolts ” 1/2-13×3-1/4 / July 3, 2026 Hex Head Bolt 1/2″ – 13 x 3-1/4″ Long Grade 8 ” 4 Bolts ” 1/2-13×3-1/4. (4 Bolts ).