EPSON AcuLaser M8000 Series User's Guide
3. Remove the duplex unit connector cover.
Note:
Keep the upper option cover, lower option cover, and duplex unit connector cover in a safe place to prevent from losing it.
4.Install the Duplex Unit as shown below. Make sure that the hooks on the Duplex Unit hook onto the printer’s tabs and the duplex connector goes into the slot.
Installing Options 119