The SMBN0491 block neodymium magnet is made from high performance N52 NdFeB, with Nickel coating. The dimension of this item is 3/4″ × 3/4″ × 1/2″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.07625 lbs. It can pull up to 42.66 lbs steel. And the surface field is up to 5665 gausses.