amasky Stainless Steel Double/three Tubes High Decibel Outdoor Life-saving Emergency Whistle Strong and Durable - Stainless Steel Material ensures the whistle durable,it will last you a very long time,the max voice 150 db. Good Environmental Adaptability - Whistle has double tube and crisp sound,without pea ,not moldy,you can use it in any environment. Safety - Made of Food Grade Stainless steel,safety confirmed.Unique sounding chamber. In emergency or sports referee,the double tube design can get the same db,you can save 30% energy than normal whistle. Wide Range of Application - Perfect for referees officials coaches, training, sports, teacher, lifeguard, life-saving, protection, hiking, camping, wilderness survival, emergency,etc.