The SMBN0625 block neodymium magnet is made from high performance N52 NdFeB, with Nickel coating. The dimension of this item is 3″ × 3″ × 1/8″ thick, magnetized through thickness, with tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0190625 lbs. It can pull up to 57.5 lbs steel. And the surface field is up to 554 gauss.