The SMBN0487 block neodymium magnet is made from high performance N42 NdFeB, with Nickel coating. The dimension of this item is 3/4″ × 3/4″ × 3/8″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0571875 lbs. It can pull up to 30.05 lbs steel. And the surface field is up to 4400 gausses.