XO Guardian is a GPS based app that sends SOS messages during emergencies to the mobile numbers you have previously chosen. Recommended by many, it is currently available for Apple phones. All you have to do is select a few numbers of your relatives and friends. In case of emergencies you just need to open the app. After 10 seconds it will automatically send instant SOS messages to the numbers you have chosen. If you wish to cancel you can swipe the button to exit SOS Streaming.