The Hubelino Pi marble run system is designed for older children. Pi combines daring physics tricks with creative construction fun. The fascination of constructing tricky marble run racetracks is only topped by the high speed and action-packed tricks and stunts of the steel marble. And best of all, Hubelino Pi is fully compatible with other building bricks, figures and theme worlds. The exciting Gauss cannon mechanism repels the opposing steel marble forward and onward at great speeds. You can reposition the cannons wherever you'd like on the track. For ages 8 and up. WARNING: CHOKING HAZARD - Small Parts. Not for children under 3yrs. WARNING: CHOKING HAZARD—Toy contains a marble. Not for children under 3 yrs.