731821000000 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 - NON-THREADED ARTICLES : SPRING WASHERS AND OTHER LOCK WASHERS, 853690000000 under HS Code Others, and 843149000000 under HS Code Others were the top imported HS Codes by S & T MARBLE AND MINING LIMITED in 2021.