Good Materials: This double tube whistles is make from good aluminum alloy materials, can be used for long times. Loud Whistles: This high frequency is loud, and the transmission distance is long, very useful for various emergencies situation. Easy to Use and Carry: This small aluminum alloy whistles is small and light weight, can being hanging on the keyring as ornament. Multipurpose: Emergencies tool aluminum alloy whistles for variety of occasion, such us camping, hiking, boating, . Package includes: 100Pcs Lifesaving Whistles