The interactive ball track system from Ravensburger. Fun for all ages! Connect the GraviTrax Junior to your GraviTrax ball track and vice versa with this handy Adapter Set. With the help of a few adapters, the ball rolls from the GraviTrax world to the GraviTrax Junior world and back again—for even more exciting tracks. With the GraviTrax ball track system, you can playfully discover gravity, and with various expansions, it can be expanded for limitless building and play fun! Add even more speed with the expansion sets.