JMY211(Hard ferrite): When the antenna of the reader is in the environment of much more metal materials, to install the board of ferrite at the back of antenna, so that lowering the effect of metal materials for the performance and stability of the reader when reading card. It is verbose to produce hard ferrite. It need to make new mould and process by machine, but the performance of hard ferrite is better than soft ferrite. The hard ferrite is firm, so the size need be custom-made.