The SMDN0071 disc neodymium magnet is made from high-performance N52 NdFeB, with Nickel coating. The dimension of this item is 7/16″ dia. × 1/16″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.00254375 lbs. It can pull up to 3.23 lbs steel. And the surface field is up to 2033 gausses.