1. Female dark night home alone or, in case of a suspicious person near or trailing, can pull bolt, deter suspicious people, give up their evil thinking.

2. go out shopping, child carry a alarm, if separated, can sound the alarm, to avoid missing.

3. elderly people suffering from acute diseases (such as coronary heart disease, etc.), carry (or night in bedside suspension) this cheap personal alarm, meet the onset of the disease, I can not say the situation, sounding the alarm could save lives.