Survival Whistle Survival Whistle Aluminum Alloy Whistle Outdoor Whistle Use: Suitable for outdoor sports such as hiking, climbing, cross-country running, hiking, etc . Size: 9*46mm Color: random color (about 7 colors) Shipping quantity: 10pcs Aluminum alloy long professional outdoor survival whistle Sound is loud, transmission distance is long. When traveling outdoors, it is can help you confirm your orientation, avoid getting lost, find a companion, etc. If you want to have the perfect outdoor walk, be sure to prepare carefully before leaving and be sure to check if the whistle is brought before leaving . Due to lighting and screen differences, the item's color may vary slightly from the pictures. Please allow slight size difference due to different manual measurement.