... attachment key ring is super powerful. Magnetic hook magnet Magnet(NdFeB magnet) is made from Neodymium,Iron,Boron and someother transitive metallic ... to make it strongGeneral FeaturesGrades:N33,N35,N38,N40,N42,N45,N48,N50,N52, (M, H, SH, EH, UH )Coatings: Ni ...