Teotihuacan Insert: - Rules of Play says:
Insert compatible with Teotihuacan® and the Late Preclassic Period® expansion. The design provides both efficient storage and improved game play. The trays can be utilised during the game, and they greatly aid set-up and clear-away times. The rules and boards act as a lid on top of the trays. The insert is arranged in two layers. The second expansion, Shadow of Xitle® can also be added to the insert trays.