[Product Name] High-Frequency Dual-Chamber Survival Whistle [Principle] High-frequency dual-cavity resonance [Features] Easy to blow and produces a loud sound, with long range of transmission [Volume]118dB [Material] Aluminum*Silicone [Dimensions] 5.6cm*15mm*0.8cm [Weight] 11 grams [Features] 1. Lightweight and equipped with a keychain, making it easy to carry; 2. Larger diameter, louder whistle sound, essential equipment for outdoor rescue; 3. Made of aluminum alloy, the surface is treated with anodized technology, which gives it a durable color that does not fade and extends its lifespan. The whistle is made of silicone and is packaged in individual OPP bags, 200 pieces per medium pack, and 2000 pieces per carton 21kg. There are various colors to choose from, thank you