National Stock Number

The NSN (National Stock Number) is the 13-digit number that the federal government assigns, for purposes of identification and inventory control, to every piece of supply, equipment and material that it uses and buys. You can think of the NSNs as a federal cataloging system based on the concept of one NSN for any one item and one single item manager for each particular class of product. (Note that, because services are not inventoried, services don't fit this model. For services, only the first four digits are used. See the discussion of FSCs, above.)

In a typical NSN, for example, 4720-00-101-9817, the first four numbers are the Federal Supply Code (FSC), which places the item in a specific category. In this example, 4720 is Pipe, Tubing, Hose, and Fittings because it starts with 47. The second two numbers, 20, identify the item as Hose and Flexible Tubing, which includes air duct, metallic, nonmetallic, and textile fiber hoses and their assemblies, etc. The next two numbers, in our example, 00, identify the country that buys the item; 00 or 01 is the code for the U.S. The remaining numbers of the NSN, 101-9817, are referred to as the National Item Identification Number (NIIN) and are used to index NSNs.

How does all of this help you? Understanding the NSN, while at first somewhat of a challenge, is one of the keys that will open up some doors of opportunity for you. The NSN classification system helps to identify the offices and agencies that have control over the item and/or buy that item. Remember, for this to be useful, you must know the complete NSN.

If you know the NSN, searching on the NIIN can assist you in finding previous buying trends, previous supplies, and procurement history. Also, if the NSN "gets lost," you can sometimes use the NIIN to locate where it was reassigned since the NIIN tends to remain with an item over time.

You can do an Internet search based on NSNs at the Defense Supply Center's web site.