Neodymium Ring Magnet 4 x 2 x 8 mm N48 Diametrically Magnetised
 
An NdFeB (neodymium) ring magnet provides high magnetic attraction for its size and fits readily into various holders and components. Compared with ferrite, neodymium provides much greater magnetic attraction. The magnet generally has a protective surface coating. N48 indicates the magnetic grade, commonly ranging from N35 to N52; higher numbers generally indicate greater magnetic attraction. This version radially magnetised: the magnetic field acts radially, with the poles on the inner and outer cylindrical surfaces. This is useful where the field needs to act from the sides.
 
The Ø4/Ø2×8 mm size suits prototypes and DIY projects, especially applications with shaft or screw mounting. (Ø4/Ø2×8 mm) The diametrically magnetised rings are often used in motors, generators, Hall sensor applications, magnetic couplings and shaft assemblies. Holding force depends strongly on the thickness and condition of the metal surface. It is greater on thick steel and weaker on thin sheet metal.
 
Warning: keep out of reach of children. Swallowing magnets poses a serious risk and requires immediate medical attention. Magnets can snap together quickly and pinch fingers. They are hard but brittle, so do not allow them to collide. Keep them away from bank cards, sensitive electronics and medical devices such as pacemakers.