85389090 under HS Code Others, 73089090 under HS Code STRUCTURES (EXCLUDING PREFABRICATED BUILDINGS OF HEADING 9406) AND PARTS OF STRUCTURES (FOR EXAMPLE, BRIDGES AND BRIDGE-SECTIONS, LOCK-GATES, TOWERS, LATTICE MASTS, ROOFS, ROOFING FRAME-WORKS, DOORS AND WINDOWS AND THEIR FRAMES AND THRESHOLDS FOR DOORS, SHUTTERS, BALUSTRADES, PILLARS AND COLUMNS), OF IRON OR STEEL; PLATES, RODS, ANGLES, SHAPES, SECTIONS, TUBES AND THE LIKE, PREPARED FOR USE IN STRUCTURES, OF IRON OR STEEL - OTHER : OTHER, and 73181600 under HS Code SCREWS, BOLTS, NUTS, COACH-SCREWS, SCREW HOOKS, RIVETS, COTTERS, COTTER-PINS, WASHERS (INCLUDING SPRING WASHERS) AND SIMILAR ARTICLES, OF IRON OR STEEL - THREADED ARTICLES : NUTS were the top imported HS Codes by GAS TRANSMISSION COMPANY LIMITED in 2023.