The original trays were printed as once piece. These trays are printed with the arms separately which eliminates the time needed to move between arms during printing.Print four copies of the in tray arms and attach to a tray base. Print four copies of the out tray arms and attach to a tray base. Attach trays to the rest of the Jack the Ripper Bot. For more details on this project see Jack the Ripper Bot and https://github.com/ajayre/JacktheRipperBot.