Purchased about three years ago at a seminar held by the International Brain Update Association. Since it corresponds to the five elements of the Yin-Yang and Five Elements theory, I also purchased the Five Elements Metaphor Handbook from Touch for Health Japan at the same time. Although I bought them, I haven't had a chance to use them, and both the tuning forks and the handbook are almost unused. I will select the frequency I need now from the five elements and adjust it with the sound. It seems that it can also be used to adjust the space or the place. Set Contents ・Five tuning forks corresponding to the five elements, case - Tuning fork colors: Silver (Metal), Green (Wood), Blue (Water), Red (Fire), Gold (Earth) ・Manual ・Touch for Health Five Elements Metaphor Handbook - The cover has a small tear, but the main body has no scratches or stains. Thank you for looking.