3 years & up. Children will explore the worlds of shape, space, and magnetism all in one exercise while combining the fun of construction with the lessons of polarity. These magnetic builders connect on every side and angle with fully contained magnets. One side of each piece is colored while the other is black allowing children to understand which sides attract and repel. Squares are 2 3/8". Starter set includes 32 pieces in 2 shapes and 6 colors. Class Set includes 96 pieces in 2 shapes and 4 colors.