Retailers in the UK and Germany have listed a new accessory for Nintendo's Wii U game console. More specifically, they have listed an aftermarket battery for the Wii U GamePad. The high-capacity battery was originally announced in Japan months ago, on May 30th. This new battery pack has a rating of 2500 mAh and promises to offer up to 8 hours of gameplay before you'll need to plug it into the wall again, which is double of what the GamePad's default 1500 mAh battery offers (between 3 to 5 hours). The price for this battery pack? £25 in the UK and €35 in Germany.