3 in 1 multifunction, besides emergency whistle, it is also a compass and thermometer, providing you with necessary information when exercising outdoors. Loud safety whistle, suitable for camping, hiking, biking, skiing and other outdoor activities, also can be used for coaches, coaches, sports, teachers, life saving, protection self defense.In the event of an emergency on the water, a whistle can save your life. Sturdy and loud. Just the right tone, commanding authority. The inside ball can be frozen in very cold weather. If this happens, try spraying some dry silicone inside to spray the ball.EASY TO HEAR - 3 super loud survival whistles can deliver up to 120 decibels of sound to be heard from long distances and come into play in an emergency