The SMDN0153 disc neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 3/4″ dia. × 3/8″ thick with step OUT, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0491875 lbs. It can pull up to 28.34 lbs steel. And the surface field is up to 4339 gausses.