Launch more marbles with the “GraviTrax Balls & Spinner” and up the odds on your races! With the spinner up to six balls can be started at once. Watch as the marbles are sent on a race through your tracks. This extension allows you to build up to six different track courses. Combined with the Starter-Set, you could have up to nine different tracks launched at once. How many marbles will you race? Comes complete with 1 Spinner, 6 metal marbles and instructions.