Robotime-ROKR mechanical gear marble run. Based on real-life lift coaster, Marble Run series will excite your imagination and creativity while building the mechanism. Rotate the crank and watch marbles go crazy down the slopes and turns! That brings you hours of fun and inspiration. Perfect gift at any occasion: for quality time shared between family, a birthday present& pastime for friends, etc. Detailed design and attractive appearance also make it a delight to eyes.