The SMCN0320 cylinder neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 1/4″ dia. × 3″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0399375 lbs. It can pull up to 4.45 lbs steel. And the surface field is up to 6594 gausses.