Samsung Xpress SL-M2835DW/XAA User Manual page 28

Media and tray
Paper type available for duplex printing
Duplex printing might not be available for some models (see "Features by model" on page 6).
Depending on the power voltage your machine uses, available paper types for duplex printing differs. Refer to the below table.
Power voltage
110V Letter, Legal, US Folio, Oficio
220V A4
Available paper
28
2. Basic Setup