The SMDN0149 disc neodymium magnet is made from high-performance N42SH NdFeB, with Nickel coating. The dimension of this item is 3/4″ dia. × 1/4″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0299375 lbs. It can pull up to 18.82 lbs steel. And the surface field is up to 3661 gausses.