Don’t lose your marbles! Our handy “GraviTrax Ball Box” set holds 24 of those shiny spheres you love to watch fly down your GraviTrax race track! With 4 stackable boxes included (2 green, 1 white & 1 grey), you can organize your marbles by color or just mix them up as you like. We’ve included a dozen new marbles; 6 silver and 2 each of red, blue and green. A great accessory to add to any GraviTrax product! Experience the power of gravity and educational fun today and build beyond the usual!