Z-fIt 1 iPhone 6 Case Charger Compact, Slim, Lightweight Design, Powerful 3500 mAh Lion Lithium Polymer Battery Removable/Rechargeable Power Cover How we are different: iPhone charger contains 3500 mAh battery with one year warranty unlike most brands which contain less powerful battery Tell me the features: Ultra slim, does not add the bulk, elegant design How are operations: Featuring lightning connector to charge iPhone and micro-USB port for power input How to tell how much battery remaining: Power LED indicator - will indicate the level of power your battery case is currently charged