The SMSN0749 sphere neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 3/4″ diameter, with the tolerance of ±0.004″. The weight of this super strong neodymium magnet is 0.059875 lbs. It can pull up to 14.74 lbs steel. And the surface field is up to 8815 gausses.