K'NEX Mario Kart Wii Ultimate Building Set - Bowser's Castle Parts to build Mario and Luigi 2 Karts with super-fast battery-powered motors Multiple moving obstacles like Thwomps, Fireballs and Fire Cogs 4 collectible items from the game: a Mushroom, a Green Turtle Shell, a Banana Peel and Bullet Bill! 26 pieces of double-wide, buildable, inter-connectable track that creates a multi-level, closed-circuit Bowser's Castle Track!