Neodymium magnets are all graded by the material they are made of. As a very general rule, the higher the grade (the number
following the ‘N’), the stronger the magnet. The highest grade of neodymium magnet currently available is N52. Any letter
following the grade refers to the temperature rating of the magnet. If there are no letters following the grade, then the magnet
is standard temperature neodymium. The temperature ratings are standard (no designation) – M – H – SH – UH – EH.