Iphone 6 Battery Case, ST-CASE&reg; 3800mAh Rechargeable Detachable Extended Backup Battery Case Power Bank Pack Cover Battery Replacement Charger Case for iPhone 6 4.7 inch (Black) Intelligent charging system with Smart power indication Rechargeable li-polymer battery pack, recycle use for protect the environment. Popular in many countries and enjoyed good reputation from customers Portable and convenient, perfect extended backup battery case for iPhone 6 and 6s Security and stability, Protective circuit for overcharging, over using and short circuit.