Neodymium Disc Magnet 4 x 1 mm N48
 
A neodymium magnet (NdFeB) is small but very strong. It is made from a special alloy and magnetised in a strong magnetic field during manufacture. It is noticeably stronger than conventional ferrite magnets and generally has a protective coating because the material is prone to corrosion. N48 indicates the magnetic grade; a higher number generally means a stronger magnet, with grades commonly ranging from N35 to N52.
 
This very small size is often used in electronics, sensors, model making, prototypes and precision mechanics where an unobtrusive attachment is required. Even a small gap caused by thick paint, tape or an uneven surface noticeably reduces holding force. It performs best on solid steel.
 
Warning: keep away from children. Two magnets can snap together quickly, pinch fingers and crack or chip. Use spacers for storage and take care when separating them. Keep them away from sensitive electronics, cards and medical devices.