The SMBN0441 block neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 1/2″ × 3/8″ × 1/4″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0126875 lbs. It can pull up to 10.51 lbs steel. And the surface field is up to 4759 gausses.