Colt Express Rock Promo Accessory
A promo from the 2016 Easter Basket (Brettspiel Osternest).
It consists of a small folded board with the following instructions:
"This Rock decoration can be used to place your common deck during your Colt Express games, with or without the third expansion (Indians & Cavalry)
In Colt Express, you play a bandit robbing a train at the same time as other bandits, and your goal is to become the richest outlaw of the Old West.