| InvCode | Code that identifies an inventory item. |
| InvCodeApplication | An enumerated type that identifies whether the InvCode is a single item which can be inventoried or a group of items which can be inventoried. Values are: Does Not Apply, Inventory Code, Inventory Grouping Code. |
| InvType | A value that indicates the type of inventory for which this request is made. If the inventory item is a room, typical values could be double, king, etc. |
| InvTypeCode | Specific system inventory type code. If the inventory item is a room, typical values could be room type code, e.g.: A1K, A1Q etc. Values may use the OpenTravel Code list or a code specific to the property or hotel brand. |
| IsRoom | Simple indicator to detect if inventory is a room. |