Material: Neodymium Magnet Type: Permanent Coated: Ni , Zn etc. Shape: Ring Size: According to your dimension ... Circle Magnet1)Suitable for marking small volume magnet with complex shape;2)Regular shape, precision size,various coating; 3) ... Widely used in industrial automation, mine, motor, communication, petroleum, magnet separator, medical treatment, Hifi acoustics, computer, Aviation, testing ...