The SMBN0396 block neodymium magnet is made from high performance N42 NdFeB, with Nickel coating. The dimension of this item is 1/4″ length × 1/4″ width × 3/16″ thick, with step OUT, magnetized through thickness, with tolerance of ±0.004″ x ±0.004″ x ±0.004″. The weight of this super strong neodymium magnet is 0.0034375 lbs. It can pull up to 4.04 lbs steel. And the surface field is up to 5159 gausses.