Definitions and Concepts > NSN: National Stock Number

The National/NATO Stock Number (NSN) is a 13-digit identifier composed of three portions: FFFF-CC-SSS-SSSS, a Federal Supply Class (F), Country Code (C), and Stock Number (S). Per Mil-Std-129, the NSN should be entered with hyphens, and any prefix or suffix specified in the contract or solicitation. The hyphens also help MIL-Comply recognize the NSN when it appears with a prefix and/or suffix, which are three and two characters, respectively, and may be separated by spaces from the NSN, e.g. 'ABC 1234-01-123-1234 XY'