These energy bands are packed with 1800 negative ions. Negative Ions are good for us! Positive Ions are not. Negative Ions can be found naturally in fresh air, plants, moving water like waterfalls or on the beach, forests & mountains. Negative ions help the body eliminate Positive ions found in computers, cell phones, air pollution, smoke, and allergens in the air. The result is increased energy, balance & flexibility. Size Small fits wrist 6” to 6 ¾”. Medium fits 6 ¾” to 7 ¼”.