The SMBN0490 block neodymium magnet is made from high performance N42 NdFeB, with Black Rubber 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 34.46 lbs steel. And the surface field is up to 5053 gausses.