The SMBN0517 block neodymium magnet is made from high performance N42 NdFeB, with Nickel coating. The dimension of this item is 1/2″ length × 1″ width × 1/4″ thick , with step IN, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0315 lbs. It can pull up to 18.93 lbs steel. And the surface field is up to 3887 gausses.