Lifesaving zipper / Emergency rescue

In case of dangerours situation in the wild field, such as falling hurt, getting lost,a long time of crying for help would make people in distress and tiredness. Generally,the sound of calling for help can only transfer withinlimited distance, thus may not draw the attention of others, and thus miss the rescue.
In danger of being trapped in the wild, pull the Lifesaving zipper to the top of the collar, you can put the Lifesaving zipper in the mouth to whistle. A loud whistle travels farther than a human voice, and saves more energy than calling with throat. It can improve the chances of being rescued.