Chocolat,good that you open your mind to know about -ve ion,,strongly advise you to get those with far infrared rays combine with -ve ion, the same brand as mine..not costly actually...to regain your health again.
I spent a bomb whole of last year from natskinctr,hospitals, oral supplements,moisturisers,etc,sufferings , end up this cheaper alternative non oral non steroid that get me back to health...cost can't be measure when health is priceless...(speak from own experience).
there are too many diff brand with too many diff types of stones,etc,etc adding in and these are very complicated, making it too costly.
SUMMIT brand is simple and effective. Feel free to let me know if you want to see actual product to test...do your marketing research properly amongst many diff brands...get from those that able to share with you real testimonies...not those , through mouths of mouths...