The outer surface is well polished and acid etched to protect it from scratches and oxidation2. Light weight for daily use3. Easy to whistle and make a loud sound in the open air4. Survival signal whistle, ideal for outdoor sporting events, outdoor camping, hiking, boating, etc.5. The overall quality of brass to build, exquisite workmanship Specification: Description:This is a bamboo section style brass whistle, you can use it when you are in an extreme environment or in an emergency state that you can use less effort to whistle for help. The whistle is made from brass and exquisite workmanship. Through the polishing and pickling process, which can effectively protect the pole, and not easy to scratch and oxidize. The peculiarity of brass is that during its oxidation process, different colors will have different beauty. After oxidation, you can use sandpaper or toothpaste to wipe clean, and it can return to the original brass color. This survival whistle, ideal for outdoor sporting events, camping, hiking, boating, etc.Features: With excellent airflow design, it can easily whistle and produce a loud and clear sound.2. Lightweight and convenient to carry.3. The overall quality of brass to build, exquisite workmanship.4. Through the polishing and pickling process, which can effectively protect the pole, and not easy to scratch and oxidize.5. Apply to outdoor survival, life saving and collecting.Features:Material: Brass Color: As shown in the pictures Length: Approx. 54mmDiameter: approx. 10mm Weight: approx. 21gPackaging: Thick PP BagPackage Included:1 x Brass WhistleNote: Please allow 1-3mm error due to manual measurement. Thanks for your understanding.2.Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please in kind prevail.