The 13-digit national stock number is a 13-digit numeric code, identifying all the 'standardized material items of supply' as they have been recognized by all NATO countries including United States Department of Defense. It consists of the 4-digit Federal Supply Classification code and the 9-digit National Item Identification Number. The National Item Identification Number consists of a 2-digit National Codification Bureau number designating the central cataloging office of the NATO or other friendly country which assigned the number and a 7-digit (xxxxxxx) nonsignificant number. The number shall be arranged as follows: 9999-00-999-9999. An item having an NSN is said to be "stock-listed".