WIDELY USED: This survival whistle is a great tool for outdoor activities such as camping, fishing, hiking, and hunting, saving lives in emergencies. Loud sound: Dual tubes can reach up to 150 decibels, making it audible from far away.SMALL AND LIGHTWEIGHT: Easily carried on your keychain, convenient and practical. It can be attached to your backpack, belt, or attached to a lanyard or keys.HIGH FREQUENCY DESIGN: The whistle has a high volume, a long propagation distance, a loud sound, strong penetration, and high detection. At the same time, the sharp tone will not hurt your ears. The sound effects can range from quiet to loud. Depending on how you whistle, the volume changes; the sound is loud and clear and easy to play. .STRONG AND DURABLE: The metal whistle is made of aluminum alloy, ensuring the whistle is durable and safety assured. The whistle has no built-in pea, so it won't mold or breed bacteria. You can use it in any dusty or dirty water environment.