Rear-earth Magnets N45SH grade Ring shape,spec.17X8X40 Zn coating for pump motor Surface Treatment practicable: ZN,Ni,Tin,Gold,Epoxy,Parylene,Plastic packed, Telphlone Dimension RangeOuter Dia(1-180)mm, Inner Dia(1-150) Thickness(0.5-40)mm Grade Available:full grade for pump pump magnetRare earth ring magnet for pump