ISO/IEC 15459-5:2007 specifies a unique, non-significant string of characters for the unique identification of returnable transport items (RTIs). The character string is intended to be represented in a radio frequency identification (RFID) transponder, bar code label or other automatic identification and data capture (AIDC) media attached to the item to meet supply chain management needs. To address management needs different classes of RTI are recognised in the various parts of ISO/IEC 15459, which allows different requirements to be met by the unique identifiers associated with each class. The rules for the unique identifier for RTIs, to identify the unique occurrence of an item, with the identity being relevant for the complete life cycle of the item, are defined and supported by an example.