The SMDN0148 disc neodymium magnet is made from high-performance N52 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 23.3 lbs steel. And the surface field is up to 4105 gausses.