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.
