The SMBN0541 countersunk neodymium magnet is made from high-performance N42 NdFeB, with Nickel coating. The dimension of this item is 1″ × 1″ × 1/2″ thick w/ hole to accept a #10 screw, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.12375 lbs. It can pull up to 48.45 lbs steel. And the surface field is up to 3916 gausses.