Features: . Battery pack designed for Wii fit . Built-in Lithium-ion battery provides using convenience (just put the battery pack into the place in Wii fit) . Rechargeable either in or out, when charging . LED indicator is in red while charged in green Using method: . Insert the DC plug of the USB charging cable into DC jack of pack (pay attention to insert it completely) . Insert USB plug into USB port in Wii console, in computer or in any power adapter with DC 5V output . LED indicator lights red when the pack is charging . LED indicator lights green when the pack is charged . When finish charging, please pull the USB charging cable out of the Wii console or computer before cut off DC plug and battery pack . Attachment of product brings no trouble to Wii fits work or attachment of other accessories . Replacing Wii battery pack helps Wii fit be easer used 500 times charging available eliminates the need of frequent replacement of batteries . USB charging and convenience . Strong points: . Attachment of product does not obstruction to use other accessories . Super great capacity adds the playtime . Charging model: Constant voltage + constant current + purling current, auto cut-off when completely charged and overcharged impossible . Specifications: . Charging current: 500mA . Charging voltage: 5V . Capacity: 700 to 1, 800mAh selectable . Charging last: 700/1.5, 1, 000/2.2, 1, 200/3 and 1, 800mA/4 hours Charging method: . Do charge when use it for the first time or won't use it for long time . Charge at least once in every three month 500 times charging available but for environment or its property, using time's contraction is normal after its repeating charging and discharging