Item Unique Identifier Type Code 

Type - Data Synonym
Description: A designator to indicate which method of uniquely identifying a part has been used. Denotes whether UII Construct #1, Construct #2, or defines the equivalent. Acceptable equivalents include: Global Individual Asset Identifier (GIAI), Global Returnable Asset Identifier (GRAI), Vehicle Identification Number (VIN), or Electronic Serial Number ((ESN), for cell phones only). 
Information Exchange: Evidence of Goods Tendered and Services Rendered from External