Multi Frequency Survival Whistle: This emergency whistle is designed to emit high, medium, and low frequency distress signals. The low frequency sound is powerful and can be heard close range even in noisy environments. The high pitched sound effectively attracts attention, making it ideal for emergency or alarm situations.Clear and Loud Sound: With a crisp and loud sound that carries over long distances, this Emergency Whistle is great for calling for help or gathering companions in outdoor survival scenarios.Convenient to Carry: This Survival Whistle can be easily attached to tents, equipment, water bottles, backpacks, key rings and other accessories; making it a handy tool for any outdoor adventure.Versatile Use: Made of reliable plastic material that withstands wear and tear; this Outdoor Safety Whistle is practical and convenient for various outdoor activities such as camping, hiking, fishing or traveling.Product Specifications: The package includes 10 multi frequency survival whistles with dimensions of 7cmx2.7cmx0.7cm/2.76inchx1.06inchx0.28inch each. Size Chart: 7cmx2.7cmx0.7cm/2.76inchx1.06inchx0.28inch Package Includes: 10 Outdoor Survival Whistle Note: Please allow slightly errors 1-2cm differences due to manual measurement.