Battery Life Advice: The flashing lights on this shoe are battery operated, and have a motion sensitive action. The battery in this unit is not replaceable and the life of the battery is subject to wear. The wearing performance of this shoe is not affected by battery life.WARNING! CONTAINS BUTTON OR COIN CELL BATTERY. HAZARDOUS IF SWALLOWED. Button Battery Warning: More information: https://www.productsafety.gov.au/products/electronics-technology/button-batteries