When a marble enters the Helix it will move down to a lower level without changing its direction. Up to six marbles can pass through this Action-Stone at the same time!\nBuild new routes and create crazy trick shots, expand the marble run with new ideas, expansion sets to keep the ball rolling compatible with all GraviTrax & GraviTrax PRO sets & accessories\nExperiment with gravity to power your ball through twists, loops and turns in a race to the finish line great building game for boys & girls\n\n\nThe GraviTrax track system can be extended indefinitely with extra track packs and add-ons each sold separately.\n\nSuitable for ages 8 years and up.\n\nTHIS IS AN ADD ON PACK – A STARTER SET IS REQUIRED TO PLAY\n\n\n**All GraviTrax and GraviTrax Pro products are compatible**