These water glasses are made of high quality copper and stainless steel. Copper is slightly soluble in water, so water kept in these glasses inhibits the growth of Bacteria, Viruses and Fungi. Beside this water kept in this set clears the waste attached with intestinal wall & keeps the stomach free from all stomach diseases. Body and makes a person cheerful. The inner side where water is filled is made in pure copper while outer side is made in stainless steel.