Description Ages: 7+ ages, both for kids and adults. Operating temperature: 80 degree Celsius/176 Fahrenheit Magnets Type: Neodymium. Disc Size: diameter 100Pcs Diameter3mm x thickness1.5mm. 50Pcs Diameter8mm x thickness1mm. 50Pcs Diameter5mm x thickness2mm 50Pcs Diameter5mm x thickness 3mm.. 50Pcs Diameter8mm x thickness 1mm. 50Pcs Diameter10mm x thickness2mm. 50Pcs Diameter10mm x thickness1mm. Rating: N52 Package Included: 100PCS/50PCS Magnets. Features: 1. Super strong Rare-Earth magnets, once they get stuck with each other, they are hard to break apart. 2. Can also be used to extend protected lithium batteries with recessed contact points. 3. Electrically conductive (making them suitable to extend recessed batteries). 4. Neodymium magnets are usually coated Nickel-Copper-Nickel plating to prevent the iron from rusting. 5. Perfect for sticking notes on fridge doors. Great for do-it-yourself projects.