Marble Run series currently includes the following six products, each of which is equipped with several small steel balls. Players can make the steel balls run on the track by turning the handle. This product series is all gear driven with the most widely used mechanical rotation mode. They are creative 3D wooden puzzles designed both for adults and teenagers. We select the primary design which can best embody the beauty of machines. We believe it is the coolest decoration in your study and hope it could inspire you while balls are rolling.