Please note the following information  is what appears on the  packaging of the shungite slice. Electromagnetic  fields generated  by mobile phones and other devices cause adverse effects on areas of the brain. Resulting in neuro illnesses  such as Parkinsons and Alzheimers. Electromagnetic  radiation can lead to destruction of our DNA, changing  its code in a negative way. The Shungite  slice is able to screen harmful radiation  in the range of 900MHZ   to 1800mhz and above.  ( The Act of  Compliance Labratory Karnc range of the  Russian Academy of Sciences ) It is proved that Shungite absorbs more than 50% of phone radiation. Instructions for use : peel back adhesive and fasten shungite  plate to the back of your phone.