At the bottom right of the Capt-back, there is an extension at the top of a cupholder for a mug in place and the front ashtray.

Everything is made out of mdf wood. The cup holder is made from a plastic drinking cup for toddlers.

The dummy ashtray is a reverse case in which one business cards in stores.

Additional explanations and illustrations are to be found at the following link:
https://www.flightdeck737.be/hardware/platform/aft-flight-deck/onderfdelen-achterwand-capt-zijde/uitbouw-drinkbekerhouder-met-dummy-asbak/