Item property association entry data.
| Name | Type | Description | Notes |
|---|---|---|---|
| toString() | String | Text summary of the box. |
| Name | Type | Description | Notes |
|---|---|---|---|
| essential | boolean | Set to 1 indicates that the associated property is essential to the item, otherwise it is non-essential. | |
| property_index | int | Is either 0 indicating that no property is associated (the essential indicator shall also be 0), or is the 1-based index of the associated property box in the ItemPropertyContainerBox contained in the same ItemPropertiesBox. |