This ultimate rescue whistle is made of stainless steel with a louder sound for emergencies and in sports referees, the double tubes can deliver up to 150 decibels that can be heard from afar. It is very durable Emergency whistle, it can be used in all environments in all weathers, rainy and humid with excellent air circulation design, easy to whistle and produce clear and maximum sound. Dual-tube design makes it easy to blow gently so that just the sound is loud. You can save 30% energy compared to a normal whistle. If you get separated from the group during the hike. Made of high quality stainless steel, food grade, safety confirmed. It will not harm your health. And the high quality material makes it durable, you can use it for a long time. The perfect size to attach to a keychain or backpack