A:Answer Hello. Unfortunately, the ET-5850 does not support auto 2-sided (duplex) printing for that paper size. Duplex printing is only compatible with the following paper sizes: Letter (8.5 × 11 inches / 216 × 279 mm), A4 (8.3 × 11.7 inches / 210 × 297 mm), Executive (7.25 × 10.5 inches / 184 × 267 mm), A5 (5.8 × 8.2 inches / 148 × 210 mm), B5 (7.2 × 10.1 inches / 182 × 257 mm), Mexico-Oficio (8.5 × 13.4 inches / 216 × 340 mm), and Oficio 9 (8.46 × 12.4 inches / 215 × 315 mm). Regards, Kevin - The Epson Team.