Building with magnets has never been easier or more fun. With the 2 sizes of magnetic rods (3¾" and 2½") that will either stick to each other or to the non-magnetized metal spheres, children can free their creativity by building shapes of any size and shape. The structures are very stable yet easy to take apart and rebuild guaranteeing hours of creative fun. 66 pc. set. Ages 3 yrs. +.