Neodymium Iron Boron ('Neo', NdFeB or Neodymium) Magnets are made from an alloy containing, amongst others, the elements Neodymium, Iron and Boron (NdFeB). The NdFeB magnets are the strongest type of magnet commercially available. These magnets can be bonded in place using structural adhesive and offer incredible performances through large air gaps. They are triple coated (Nickel Copper Nickel) for maximum protection against corrosion. Maximum operating temperature: 100°C. The E-Magnets 656 Neodymium Disc Magnet has the following specifications: Diameter: 12mm (15/32 inch). Length: 3mm (1/8 inch). Pack quantity: 5.