1.Materials: Neodymium-Iron-Boron 2.OD1/2" xID 1/8" x 1/8" NdFeB Magnet Rings, Ni-Cu-Ni Coating 3.ISO9001:2000, SGS, CTI... Magnet(NdFeB magnet) is made from Neodymium,Iron,Boron and some other transitive metallic elements to make it strong. General Features: Grades:N33,N35,N38,N40,N42,N45,N48,N50,N52, (M, H, SH, EH, UH )Coatings: Ni, Ni-Cu-Ni, Zn, white-blue Zn, Epoxy, Gold, and etc.Sizes: ...