Very easy to use!
Just open the app - Start charging - Lock your phone (optional) - Done!
To stop alarm - Open your phone - Swipe up/double click Home button - Close the app.
Perfect to use at the airport, your office, library, or in any place where you will leave your device unattended for a short while.
Also if you get a power failure, or if your power pack loses all the power, the alarm will go off.
Works on wireless chargers as well, since it is activated by power loss.