A NATO Stock Number, or National Stock Number (NSN) as it is known in the US, is a 13-digit numeric code

Code

A code is a rule for converting a piece of information into another form or representation , not necessarily of the same type....

, identifying all the 'standardized material items of supply' as they have been recognized by all NATO countries including United States Department of Defense

United States Department of Defense

The United States Department of Defense is the U.S...

. Pursuant to the NATO Standardization Agreement

STANAG

STANAG is the NATO abbreviation for Standardization Agreement, which sets up processes, procedures, terms, and conditions for common military or technical procedures or equipment between the member countries of the alliance. Each NATO state ratifies a STANAG and implements it within their own...

s, the NSN has come to be used in all treaty countries, where it is also known as a NATO Stock Number.