Per MIL-STD-130, UID (Unique Identification Marking) barcodes must be maintained as a readable barcode throughout the entire life of the item. Metal tags with a permanent adhesive or durable polyester labels are suitable for many environments. Further, acceptable marking processes include laser etch, chemical etch, dot peen, Metalphoto photosensitive anodized aluminum, or ink jet printing.

The following methodologies (constructs) and equivalents are approved:

• UID Construct 1 – composed of Issuing Agency Code, an Enterprise Identifier, and a Serial Number unique within the Enterprise
• UID Construct 2 – composed of Issuing Agency Code, an Enterprise Identifier, a Part Number and a Serial Number (unique within the Part Number)

The following IUID Equivalents are also approved:

• Vehicle Identification Number (VIN)
• Global Returnable Asset Identifier (GRAI)
• Global Individual Asset Identifier (GIAI)
• Electronic Serial Number (ESN), typically assigned to cell phones

Accepted Issuing Agencies:

• DoD and NATO (CAGE or NCAGE)
• D-U-N-S (Dun & Bradstreet)
• GS1 (formerly EAN/UCC)