The steel pot increases the magnetic holding force of the ferrite magnet. This achieves an adhesive force of up to 7.8 kg with a diameter of just 32 mm and a thickness of 7 mm.
Ferrite magnets can be used at temperatures of up to 200 degrees Celsius. They are also much cheaper than neodymium magnets of the same size. The holding force, on the other hand, is lower than that of neodymium flat magnets of the same size