It's a train tunnel worthy of the best amusement parks. Bring your Brio wooden train set to life with the Adventure Tunnel. It has four "real world" sound effects that are magically triggered every time a train passes through. The sounds can also be activated by pushing the button on top of the mountain. The catwalk on the mountain top is perfect for Brio character to stand and enjoy the view. 2 AA Batteries not included. This tunnel fits seamlessly with all Brio wooden railway sets.