A neodymium magnet (also known as NdFeB, NIB, or Neo magnet) is the most widely used] type of rare-earth magnet. It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. Developed independently in 1984 by General Motors and Sumitomo Special Metals, neodymium magnets are the strongest type of permanent magnet available commercially. http://www.sensmagnetics.com/ndfeb-1