These whistles operate with the press of a button instead of your mouth, allowing multiple people to use them while lowering the risk of spreading germs. Since you don’t have to blow into them, you can give verbal directions as you sound an alarm, and winded or injured people can easily activate them in an emergency. All of these whistles generate a loud, consistent sound in three different tones. Switch between the tones by pressing the button. Use the included detachable wrist strap or an optional neck strap to keep them close at hand.