http://telehealth.org/apps/behavioral/tactical-breather-mobile-app#
This app was originally developed using techniques to teach service members how to use breathing to control their stress, emotions, physiological responses to stress, and increase concentration. You can use this app effectively even if you are not in the military or a veteran. The main purpose of this app’s use is to teach you a researched breathing technique to use during times of anxiety and stress. This is an app that can be used as part of your individual therapy, or just as a relaxation tool if you are not in any kind of therapy.
http://telehealth.org/apps/behavioral/tactical-breather-mobile-app#