With GraviTrax you can explore gravity without ever getting bored, because the additional pieces allow you to expand your path to infinity. Blow more marbles. With the Volcano you can throw more marbles and energize your track. Use the Volcano together with the GraviTrax Starter-Set to make the track even more lively and fun. How high and far your marbles will be able to jump after the volcano eruption. To be used only in conjunction with Gravitrax Starter Set.