One of the most important actions in an emergency is to make your location known to those searching for you. The TOPS Whistle focuses man made air streams through harmonically tuned chambers to create a piercing shriek of 126 db making it audible over most other natural and man made noises. Due to its pea-less design, the TOPS survival even works when wet making it the perfect accompaniment to all outdoor activities near rivers, lakes, or oceans. Flat enough to fit in your pocket or attach to a lanyard, this whistle is just as useful in the city as it is in the woods. Made in USA.