An amulet. It is also used as amulet, talisman, spiritual symbol and secret symbol. That is, writing images, seeds and mantras of Buddha, Bodhisattva, Heaven and Ghost. Put it close to the body or swallow it, which can be blessed by the gods, hence the name. There are many kinds of symbols, which vary according to different interests in prayer; Moreover, it has many functions, which can eliminate the difficulties of water, fire and safety in production.