The amulet is children's safety warn device. It has two parts:the master and the sub-machine.The children who wear the sub-machine,when they get closely to the  strong electric field,electric radiation,into the water,sleep,syncope,or too far away from the adult,the sensor will receive the dangerous informations through the wireless radio sent to the master,Then it will warn(alert) and flash signal.Press the switch contact to the sub-machine also can make the master warm.In the emergency,the sub-machine can be used as an larm whistle.