Pre-defined QuickBooks Custom Field.
Other1 and Other2 are standard QuickBooks custom fields available to transactions. You don't need to enable these in the transaction template to be able to access them via the SDK. (However, those Other1 and Other2 fields and their values are viewable and printable in QuickBooks only if the transaction template has these enabled!). QBXMLVersion 6.0 or higher is required to use this property.