Oki C 3200n - Manual (Page 19)

C3200n User’s Guide
Paper Recommendations • 19
Duplex Unit (Optional) ______________
This option provides automatic two-sided printing on the same
range of paper sizes as optional Tray 2 (i.e. all Tray 1 sizes
except A6), using paper from 20 to 28-lb. US Bond (42 to 58
lb. Index, 75 to 105 g/m² metric).