If an ingoing SMS contains a specific word AND is from a specific number then an alarm will go off and call the sender of the SMS in one minute. Enough time for you to wake up and realize that the alarm has been triggered. Your contact(s) can trigger your alarm with a simple SMS and vice versa. If your opponent doesn’t have this app he will only see an SMS with the text “Panic” (by default) and your current GPS coordinates. This makes this app useful regardless of whether your contact has this app installed or not.