Native American Flute with a 2hz Binaural Beat and nature sounds. This is a C# flute in 432hz tuning.. The flute was made by Lee Nix in St. Louis, Mo.

http://farpointflutes.com

Binaural beats are a way of synchronizing your brain waves (which are measured in hertz) with the hertz of the binaural beat. The brain has a frequency following response which causes this to occur. These can help induce states of relaxation, meditation and help to relieve anxiety and stressed out states. This works best with headphones because binaural beats are panned hard left and right which forces the brain to synchronize the two tones. The tone is C#, 68.05hz.

Here is an article from Wikipedia about Brainwave Entrainment:
en.wikipedia.org/wiki/Brainwave_entrainment

The brainwave states (Beta, Alpha, Theta, Delta) are listed on this page (scroll down to the table)
en.wikipedia.org/wiki/Electroencephalography

here's a basic rundown of the brains states:

Beta - 30hz-13hz - your normal awake state, in higher ranges or above 30hz you may be experiencing stress. In this case, you gotta chill!

Alpha - 13z-8hz - a relaxed and reflective state

Theta - 8hz-4hz - a very meditative state or getting drowsy and drifting off, if your sleepy)

Delta - 4hz and below - deep sleep or a very deep meditative state. Buddhist Monk's brainwaves have been measured in this state during meditation.

In the unlikely event that you experience any unusual physical or mental discomfort, immediately discontinue use.
http://sonicyogi.com