Neodymium Magnet in Steel Housing with Countersunk Hole 35 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. Compared with ferrite, neodymium provides much greater magnetic attraction. A protective surface coating helps improve durability. The N indicates the magnetic grade. NdFeB grades commonly range from N35 to N52, with higher numbers generally indicating stronger magnets. The with Hole design allows stable, repeatable screw mounting.
 
At 35×13×5 mm, this magnet provides strong, stable attachments for jigs, tools and removable assemblies. Even a small gap caused by paint, tape or clearance noticeably reduces magnetic attraction. It performs best on solid steel. Do not overtighten the screw when securing the magnet. Neodymium can break under impact or pressure. Use a washer or spacer if necessary.
 
Warning: keep away from children. Strong attraction can cause pinching injuries, and the magnets may break. Store them with spacers. Keep them away from bank cards, sensitive electronics and medical devices.