Widely used: This survival whistle is a great tool for outdoor activities, such as camping, fishing, hiking, hunting, saving lives in an emergency. Louder sound, double tubes can reach 120 decibels, which can be heard for far away . Signal: If you lose contact with your friends in the mountains and the phone has no signal, you can whistle and then stay where you are and wait, waiting for your friend to be rescued. Strong and durable: whistle metal, aluminum alloy ensures that the whistle is durable, safety confirmed. The pipe doesn't have a built-in pea so it won't mold and breed bacteria because of the pea.You can put it in anyone Use dust or dirty water environment Small and light: Can be carried easily on a keychain, convenient and practical, can be attached to your backpack, if necessary, belt, which can be attached to a lanyard or key. Small gift: Aluminum alloy whistle can be used as a creative gift for friends or kids. Package includes 2 x Whistles with keychain