Enjoy 18 continuous hours of power and rechargeability with the KMD(r), Xbox 360(r), Battery Pack! The 3900mAh battery will ensure uninterrupted gameplay all day, whether you're battling terrorists, exploring new worlds, going old-school on Xbox Live (r), or taking down terrorists. Compatible with any Xbox 360 controller. Up to 18 hours on a charge. Play while charging with this high-quality/3900mAh "Plug-in".