Key features of the Energy Pak for Wii Balance Board include:

• Rechargeable lithium-ion battery pack eliminates the need for wasteful and expensive disposable batteries
• Up to 20 hours of play time per charge, or leave it plugged in for unlimited energy
• Conveniently installs on the underside of the Balance Board, with easy access to detachable AC plug for quick and efficient charges without flipping the board
• LED charge / battery indicator
• Supports all games that require the Balance Board