Aluminum Alloy dual frequency Survival whistle dual tube outdoor Survival whistle Material: Aluminum alloy Peak volume: about 120dB Surface treatment: oxidation + sand blasting Size :55 * 15 * 8mm The colors are silver, black and gold Whistle features: 1. Whistle stable and durable: high quality aluminum alloy material, surface oxidation and sand blasting effect, not easy to fade, long service life. 2: Outdoor whistle double tube design: the volume can reach 120 decibels, long distance can hear loud sound The whistle blew. Purpose of whistle: The whistle is versatile: Perfect for outdoor camping, hiking, boating fishing, emergency survival, school sports events and lifeguard rafting. Note: 1. Allow 0-1 inch error due to manual measurement. Thank you for your understanding. 2. The display is not calibrated consistently, and the color of the item shown in the photo may be slightly different from the real thing.