Description: 10pcs N50 3mmx1mm Strong Round Magnet Rare Earth Neodymium Disc Magnets Specification: Material: NdFeB Grade N50 Size: 3mm Dia x 1mm Thick +/- 0.1mm Plating: Nickel-Copper-Nickel (NiCuNi) Triple Plating Magnetisation Direction: Through the Thickness - Poles are on the Circular Faces Max Usable Temperature: 80oC/176oF Applications: Acoustic field: the speaker, receiver, microphone, alarm, stage audio, car audio and so on.