External Battery case for iPhone 4 More than 1X your battery! Talk Time: up to additional 4 hours(3G Network) up to additional 8 hours(2G Network) Internet Use: up to additional 4 hours (3G) up to additional 4.5 hours(Wi-Fi) Standby Time: up to additional240 hours Audio Playback: up to additional 17hours Video Playback: up to additional 5 hours Specifications: Weight:58gCapacity:1300mAhCell type:Li-Polymer batteryDimension:126 x 65 x 20 (mm)Output Voltage:5VOutput Current:500 mA maxCycle life:500 timesThree LED lights indication: Press on the button to indicate real power in Battery Case LED light from left to righ. 1st LED light shine power <30% 2nd LED light shine power 30-70% 3st LED light shine power 70-100% LED Light Press twice the button continuously to open and close the LED Light. Sync When using Battery Case with your iPhone,you cna sync your iPhone to itunes without removing Battery Case ON and OFF Our Battery Case with a power switch,It`s optional for user to charger their iPhone or not. Safety Quality Control We choose grad "A" cells,Janpanese or Taiwanese made protection IC circuit and other highest quality raw materials. We conduct 16 tests on each stage of assembling process startion from every parts, work-in-progress, to final products. If you interested in our products,please go to our website: w-w-w.osmartchina.com to get more informations. We look forward to long-termbusiness with you Welcome to feel free to contact us!