Section 15 BASE METALS AND ARTICLES OF BASE METAL 74 COPPER AND ARTICLES THEREOF 74 15 SCREWS, BOLTS, NUTS, SCREW HOOKS, RIVETS, COTTERS, COTTER-PINS, WASHERS, 74 15 21 WASHERS (INCLUDING SPRING WASHERS) OF COPPER Commodity Code Description 74 15 21 00 WASHERS (INCLUDING SPRING WASHERS) OF COPPER