The duplex units offers the capability to print on both sides of the paper.
OKI B8300 Duplex Unit (B83D), 60-105 gsm, A3, B4, A4, A4R, B5, B5R, A5R, Legal, Letter, Executive, 11 lbs (5 kg), 4.53 x 16.2 x 16.4" (115 x 412 x 416 mm)
OKI B8300 Duplex Unit (B83D). Media weight (tray 1): 60-105 gsm, Media size (tray 1): A3, B4, A4, A4R, B5, B5R, A5R, Legal, Letter, Executive. Weight: 11 lbs (5 kg), Dimensions (WxDxH): 4.53 x 16.2 x 16.4" (115 x 412 x 416 mm)