This whistle made of aluminum alloy, lightweight and sturdy, can accompany you through the year, also works well in the rainy days.It features double-tube that can produce high-decibel sound, you can hear it from a distance, useful in games or emergencies.suitable for outdoor activities such as camping, hiking and boating, also applied to pet training, good gifts to your family members when going out or as coaches, referees and lifeguards' working whistle.each whistle has a key ring on the top, which is conveniently attach to keys or bags, so you can always take it with you