The SMBN0403 block neodymium magnet is made of high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 1/4″ × 1/4″ × 2″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.033875 lbs. It can pull up to 5.58 lbs steel. And the surface field is up to 6584 gauss.