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Supply Bulletin (SB) 708-21. The national item identification number (NIIN) is the second part of the NSN. It has two parts. The first part, the National Codification Bureau (NCB) code, is a two-digit number assigned to each country using the NIIN System. NCB code 00 represents the United States. (NCB codes 00 and 01 arc assigned to the United ... ................
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