PortableBattery for iPhone 4 (1900mAh)-- Backup Battery Key Features and Functions: 1.CombinesabatteryandcasewithUVcoating. 2.Lightweightlow-profile&delicatedesign. 3.ChargeiPhoneandextrabatterysimultaneously. 4.Powerful,safebatterycell. 5.LEDbatterychargestatusandchargeprogressindicator.Techniquespecifications:1.Battery:Rechargeable1900mAhlithiumbattery. 2.Input:DC5V,500mA. 3.Output:DC5V,550mA. 4.Standbytime:Upto300hours. 5. Battery Charging Time: 3-4 hours. 6. Charging for iPhone time: 2-3 hours. 7.ProductDimensions:125X62X18mm. 8.ProductWeight:65g/pcs. 9.CE&RoHS Accessories: Charger for iPhone: 1pc USB charging cable: 1pc Compatiblewith: iPhone 4