... 3.Stable performance 4.Good corrosion resistance Ring magnets for speaker material: sintered NdFeB magnet;rare earth permanent ... apparatus many industrial area, like speakers, headphone, mobilephone, receiver, microphone, audio equipment, motors, wind generators, sensors, leather, toys, ... RoHS certified. 5) Use of magnetOur magnets are used for motor speaker, hardware, package, cabinet lock ,door lock ...