Build a working null of Archimedes screw! use the hand crank or attach a motor (sold separately) to watch the marbles twirl up, and then roll down again! it's the first marbleocity marble machine kit to feature colorful plastic accents! perfect for beginners; one hour build time. Triple play models can connect to one another for bigger fun! also works with marbleocity motor kit, sold separately. For ages 9 and up.