magnetic ball Neodymium Iron Boron (NdFeB) Magnet spheres make a fun puzzle. These 216 rare earth magnet spheres will provide you hours of enjoyment. Simple yet addictive, these magnets can also be used for thousands of other helpful tasks around the house. Please keep away from younger children and pets. Grade: NdFeB rare earth material N35 Diameter: 5mm(+/-0.05) (we control the tolerance tightly and never supply less material and lower adhesive force) Coating Nickel-Copper-Nickel (NiCuNi) coating, we can also make silver,gold, black nickel and shinning nickel coating. The incredible Enigma are also great for: 1. Science Experiment 2. Making Jewelry 3. Use them on the Refrigerator, White Boards, or make desk art and impress your coworkers. 4. The possibilities are endless. We are providing very high quality magnets and offering very competitive price in the market as we are original manufacturer. It is proved as we are also providing our products to many resellers. Below list are all available and Customized magnets ball also can be designed and processed by Feller Magnets Corp. According to customer requirements. Diameter: 3mm Diameter: 4mm Diameter: 4.76mm Diameter: 5mm Diameter: 6mm Diameter: 7mm Diameter: 8mm Diameter: 9mm Diameter: 10mm Diameter: 12mm Diameter: 12.7mm Diameter: 14mm Diameter: 15mm Diameter: 18mm Diameter: 19.05mm Diameter: 20mm Diameter: 25.5mm