... +Ni and Cr3+ZnSize available: 0.5-200mmShape: Block, Square, Disc, Cylinder, Ring, Rod, Bar, Stick, Tile, Fan, Ball3. ... demagnetizing, Strong corrosion-resistance, Different series, different work temperature.7. Wide Application of NdFeB, AlNiCo & SmCo magnets Speakers, Earphones, Microphones, ... our factory and cooperate with esteemed OEM!! round disc permanent magnets/ring magnets/neodymium magnets