This huge neodymium magnet is made of grade N50 high quality NdFeB magnetic material. The dimension of the magnet is 2X2X1" with the poles on the 2X2" surfaces. The center hole is 5/16" in diameter and the counter sunk is either on N pole or S pole. By default you will get half of your order on N poles and half on the S poles. All the magnets are coated with Nii+Cu+Ni triple layers. The tolerance of the magnet is +/- 0.01mm.

The magnetic characteristics of the magnet:
Gauss Rating: 14,400 Gauss
Pulling Force: 250 lbs
Application: Separation and retrieval magnets, wind generators, or science project magnets
Annotation: There is a hole of 5/16" diameter centered on flat surface

Neodymium magnets are one of rare earth permanent magnets. Neodymium magnets are also known as NdFeB magnets, or neo rare earth magnets. Since it's very strong, people also simply call it super strong magnets or super powerful magnets. The major elements of this magnet include neodymium (Nd), iron (Fe) and boron (B), or NdFeB.