Good Time? LA205--Black-Black-Universal 5600mAh USB Port Battery Charger Portable External Emergency Power Bank with Key Ring for iPhone4 4s 5 Blackberry Samsung iPod Smart Phone POWER EFFICIENT BATTERY: Invest in a high-density Li-polymer external battery pack that retains 70-80% of its capacity after 500 charge cycles. It's the daily choice of Microsoft, Lenovo, Huawei, and Motorola.