The Bucky balls Neo Cube 3.0mm is an entertainment device like no other in the world. The Cube is composed of 512 individual high-energy rare-earth magnets. This allows you to create and recreate an outrageous number of shapes and patterns. The Cube is literally a puzzle with billions of solutions. Your cube will provide you with hours and hours of unequaled entertainment! Features: 1. Size of this ball is enough 3.0mm, Magnet Grade: N35 2. This product are balls with excellent technology, it is not easy to fade after using. Can stand Long- lasting friction and strong antioxidant ability. 3. This ball passed SGS safety test. 4. For adults only. These are so super strong, they should be kept away from children.