This magnetic building set is a safe and fun solution to help broaden the imagination of kids of all ages. Explore the power of magnets, develop their talent and stimulate their interest in science. There is a steel bar molded inside the magnetic sticks, which greatly increases the magnetic strength, making the sticks very strong. This is one of the major advantages of our products comparing to other cheaper items. 66 magnet sticks and 42 steel balls are included in this magnetic building set. The length of the sticks is 1.06" and the diameter is 0.25". The diameter of the sphere is 0.5".