The national stock number (NSN) is the identifying number assigned to each item of supply. The NSN consists of the 4-digit Federal Supply Classification (FSC) code and the 9-digit national item identification number (NIIN). The written, printed, or typed NSN configuration is 1234-00-567-8901. The following terms are elements of the 13-digit national stock number:
(a) Federal Supply Classification (FSC) is a 4-digit number which groups similar items into classes.
(b) National Codification Bureau (NCB) code is a 2-digit number designating the central cataloging office of the NATO or other friendly country which assigned the national item identification number (NIIN) and is used as the first two digits of the NIIN.
(c) National item identification number (NIIN) is a 9-digit number composed of the NCB code number (2-digits) followed by 7 other nonsignificant digits.
[41 FR 11308, Mar. 18, 1976]