Tension Free Concentration - 13.7 Hz Beta Frequency Binaural Beats

歌曲	Tension Free Concentration - 13.7 Hz Beta Frequency Binaural Beats
歌手	Binaural Beats Research
专辑	Over 3 Hours of Beta Waves Total Focus & Concentration Binaural Beats & Isochronic Tones Music & Nature Sounds