The SMDN0065 disc neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 3/8″ dia. × 1/4″ thick with step IN, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0075625 lbs. It can pull up to 6.08 lbs steel. And the surface field is up to 5110 gausses.