... strength 2.have many grades:N35-N52, 33M-45M,30H-45H etc. Annular NdFeB magnet Shape: Arc(segment),Block,Cube,Cylinder ... -(33M~45M),working temperature is 100 degree. Magnet H-(30H~45H),working temperature is 120 degree. Magnet SH-(30SH~42SH),working ...