The anion is also called "The vitamin of the air". It's the best gift for health preservation from the nature. Nowadays, the human body is exposing under the cations caused by electromagnetic wave from high-tech products (e.g. Cell phone). Blood acidified, cell membrane destroyed, and imbalance of automatic nervous system...etc. Those are because the human body absorbs too many cations. Now you have an easy way to enhance the blood circulation, cell restoration,body resistance, rebalance automatic nervous system, and anti-aging. The anions of waterfall exit in the mist caused by high speed water colliding. With Kertise oxygen spa, you can obviously see the mist in water surface after activating the machine. They are so-called high oxygen anions. The figurel(right) shows that the anions produced by Kertise oxygen spa affect the human body .