Section 15 Base metals and articles of base metal 74 Copper and articles thereof 74 03 Refined copper and copper alloys, unwrought 74 03 23 Cupro-nickel and nickel silver, unwrought 74 03 23 00 Cupro-nickel and nickel silver, unwrought Commodity Code Description 74 03 23 00 00 Cupro-nickel and nickel silver, unwrought