Portable Aluminium Alloy Whistle

A variety of applicable environments, outdoor travel, military training, distress, danger warning, and so on. Made of durable aluminum alloy, strong and durable, beautiful and fashionable. Integral molding, no ball design, water, and dust can be blown. Single tube popping design, high-frequency penetration, up to 120dB, wide range coverage. Can be hung on the backpack or hung on the keychain, do outdoor survival, and training use.