This setting is used in the [PaperSizes] section in Eiglobal.ini:
PaperSize1 ... PaperSize30
The setting specifies paper sizes. However, do not modify paper sizes here. Use the Manager module to do that. For more information, see Scanner settings: Paper size and orientation (INVOICES Help topic).
[Units] section in Eiglobal.ini (describes another Papersize setting)