Name: NdFeB Rare Earth Magnet Dia. 3 up to 220mm Up to N52 max. Max. Working Temp.: 250 deg. C Coating: Zn, Ni, NiCuNi, Gol Product Name: NdFeB Rare Earth MagnetsFeatures:Size: φ3 up to 220mmUp to N52 max.Max. Working Tempeture: 250 deg. C Coating: Zn, Ni, NiCuNi, Gold, or EpoxyApplications:Speakers, esp. Mobile phone, earphone, multimedia, home and professional audio.