BEST BRAINWAVE APP!!!! Awesome I have used different brain waves and beats for over a year and these are by far the best. I don't find the cost prohibitive and don't mind because of the high quality and most of all the RESULTS. I have chronic sleep issues and have been sleeping the best that I have for a year with the Deep Sleep. I find the Anxiety and Calm tracks do exactly that...calm. And its the only one that can consistently put me into a deeply relaxed state...then to sleep. I love it. So glad I found it!!! I recommend this company and app to everyone!