Features:

• Battery Pack for Wii Balance Board
• Compatible with Wii Balance Board Power Supply
• Large Capacity Rechargeable Battery
• Batteries Can Be Charged While Board Is In Use Through a USB Cable

Editor Reviews:

Product Description:
280 mAh / 5.0v Input, 4.8v Output

Rating : - Never worked once
Good on paper but never worked, back to throw away batteries. Would not buy this again.