"Increase the possible combinations and construct even more complex ball track systems. With this set you expand your marble track system by combining the additional components with your GraviTrax starter set. This is so you can build ever bigger marble track worlds. How many detours will your ball manage before it crosses the finish line? Includes: 2 x bottom plates, 1 x transparent layer, 8 x height blocks large, 4 x height blocks small, 2 x switches, 1 x 3-in-1, 1 x swivel, 1 x target ladder, 4 x base blocks, inserts for the base blocks: 2 x catchers, 1 x free fall, 1 x splash, 1 x target.