# BT-128 — Invoice line object identifier

> https://billhorse.com/en/terms/bt-128/

Reference to an object being billed (e.g. meter number, subscription, vehicle), optionally with a scheme identifier. Not to be confused with the item identifiers (BT-155 ff.) — this points at the object the supply relates to.

## Where does it live in the XML?

- UBL: `cac:InvoiceLine/cac:DocumentReference/cbc:ID (DocumentTypeCode 130)`
- CII: `ram:SpecifiedLineTradeSettlement/ram:AdditionalReferencedDocument/ram:IssuerAssignedID (TypeCode 130)`