The chain of key buttons is the one of the metal, one ring and one ring, and the most difficult thing to do in this is the chain. The need to design a special chain mold, this mold is very high and the cost of the mold is very expensive.
Besides, the metal handicraft: the relative chain is less difficult, the main production process is mainly casting and stamping, and forging is also necessary. Whether it is casting, or stamping, or forging. All need to open the mold. Also to accompany the relevant layout.