Don’t let the compact size of the JetScream Micro Whistle fool you because, at 112 decibels, it puts out a pretty decent sound. Use it for emergencies or survival situations because its ear-piercing shriek can be heard above most natural and man-made noises. The whistle’s pea-less design won’t freeze or clog and is just as effective when wet. It is constructed of ABS plastic and is both waterproof and buoyant. You can attach to your backpack, keychain or anywhere for ease of carry.