Louder Sound,double tubes can provide up to 150 decibels,can be heard for far distance.Strong and Durable,stainless steel material ensures the whistle durableGood Environmental adaptability - The whistle has no built-in pea ,so it will not mold and breed bacteria because of the pea.You can use it in any dust or dirty water environmentConvenient and practical,with kering and carabiner keychain,can tie on your backpack,belt.
