Looped and plays in background. You don't have to press it again and again.
Notification controls.
Screen can be turned off to save battery.
Timer can be added.

S.O.S. emergency whistle - Very useful in emergency situations, when you need help or assistance, when you have no other way to call for help. It can save your life during an earthquake, after a tsunami, typhoon, tornado, an emergency or other natural disasters.