Rare earth magnets like NdFeB Neodymium-Iron-Boron magnets have the highest energy density per volume and weight and also the best demagnetizations resistance. NdFeB Neodymium-Iron-Boron magnets have a very high energy density allowing them to have very small dimensions in cylindrical or rectangular shapes. The magnet is produced by sintering and can only be processed by grinding, due to the strength and brittleness of the material. The temperature range goes from 80° up to 160 °C. Very small magnets can be produced. Disadvantages are the high raw material prices and the limited availability of special alloys.