Neodymium Iron Boron (NdFeB) magnets are composed of Nd, Fe, B, Dy, Co and other minor elements. They have excellent magnetic property and are extremely strong for their small size. NdFeB magnets are permanent, and have a high maximum energy product. Over the last 10 years, due to high ratio of performance over price, the NdFeB magnet has become extremely popular in almost all technology applications that require high performance magnets such as motors, sensors, computers, communications, medical equipment, meters, home appliances and so on.
These 5mm x 1mm magnets are great from DIY and craft projects.
WARNING: DO NOT GIVE MAGNETS TO CHILDREN, THEY ARE NOT A TOY.