Neodymium Magnet in Steel Housing with Countersunk Hole 65 x 13 x 5 mm. 
 
A neodymium magnet (NdFeB) is very strong. It is magnetised in a strong magnetic field during manufacture, providing high magnetic attraction in a compact size. Its magnetic attraction is greater than that of ferrite magnets, and the surface coating helps reduce corrosion. The N indicates the magnetic grade. NdFeB grades commonly range from N35 to N52, with higher numbers generally indicating stronger magnets. This magnet with a Mounting Hole for easy installation in a frame, holder or panel.
 
The 65×13×5 mm size provides a strong hold for practical tasks, including quick assemblies, attachments and technical projects. For good results, use a flat, clean metal surface. Any gap caused by thick paint or an uneven surface reduces holding force. Do not overtighten the screw during installation. Neodymium is hard but brittle and can chip or crack under excessive pressure. A washer can help.
 
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 bank cards, sensitive electronics and medical devices.