Connect and build using the toddler - sized magnetic bars and balls of the SmartMax Start Plus Magnetic Discovery Kit. An open - ended construction play at its finest, this kit allows kids to string the bars and balls together, learn to build 2D and 3D shapes and more. The extra - large parts are the perfect size for a toddlers grip, and are glued and ultrasonic - welded for safety. Your kids will have a field time figuring out the intuitive connections of this building set. Long bars use stronger magnets than smaller bars. Warm and cool - colored bars attract, but like - colored bars repel. This 30 - piece set includes eight metal balls, four curved bars, 12 medium bars and six long bars.