The SMBN0387 block neodymium magnet is made from high performance N52 NdFeB, with Nickel coating. The dimension of this item is 3/16″ × 3/16″ × 3/16″ thick, magnetized through thickness, with a tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0017875 lbs. It can pull up to 2.83 lbs steel. And the surface field is up to 6451 gausses.