This Mini USB salt stone lamp with changing colors is hand carved from salt excavated from the Himalayan Mountains. When the salt is heated, it releases negative ions, also known as "Vitamins of the Air." The negative ions are said to calm nerves, revitalize cells, and purify the air for a holistic experience. Due to the unique nature of Himalayan salt, no two lamps are exactly alike in shape, size or color. USB Adapter sold separately.