Alarm mode: Open the package and rotate the lock beam by 180°. When you hear the  sound, the alarm mode is on. In this mode, if an external force touches the lock body, the lock body emits a sharp and harsh alarm sound.   Normal mode: Reverse the lock beam 180° again, there is no “di” sound prompt, normal mode is on. No alarm will sound in this mode. Each hand is given a replacement battery.