The Duplex Unit Option This section describes how to install and remove the optional duplex unit. The optional duplex unit allows paper fed from either the 250-sheet main paper tray or
the 500-sheet optional paper tray to be printed on both sides.   Acceptable paper sizes
and weights for use with the duplex unit are as follows: Notes: 1.   The duplex unit should be installed before installing the 500-sheet paper tray option. 2.   If the optional 500-sheet paper tray is already installed, remove it and install the optional duplex unit. Then reinstall the 500-sheet paper tray option. Paper Size A4, Letter, 13-in. Legal (Folio), 14-in. Legal Paper Weight 16 lb to 28 lb (60 grams/meter² to 105 grams/meter²) 114 User’s Guide