Neodymium Block Magnet 20 x 20 x 10 mm N52
 
Neodymium (NdFeB) is among the strongest magnetic materials and provides substantial holding force for its size. It is much stronger than conventional ferrite magnets and generally has a protective coating because the material can corrode over time. N52 indicates the magnetic grade; NdFeB grades commonly range from N35 to N52, with higher numbers generally indicating stronger magnets. The rectangular shape is useful for frames, edges and applications requiring an elongated, stable magnet.
 
This size provides substantial magnetic attraction and is suitable for strong attachments and robust projects. Even a small gap caused by paint, tape or clearance noticeably reduces magnetic attraction. It performs best on solid steel.
 
Warning: not suitable for children. Two magnets can snap together quickly, pinch fingers and crack or chip. Separate them carefully and avoid impacts. Keep them away from medical devices and objects sensitive to magnetic fields, including cards and electronics.