IOGEAR Hard Case with Built-In Battery Pack for iPhone4 GMP2004P (Black) Hard Case with Integrated Lithium Rechargeable Battery Add Up to 10 Hours of Talk Time; Up to 4.5 Hours of Internet Use; Up to 35 Hours of Audio Playback; Up to 9 Hours of Video Playback (Your Added Power Times May Vary Depending on Settings and Use Scenario) 1700mAh Lithium-Polymer Battery Bonus Charge and Sync Cable Included for Your Added Convenience LED Illustrates Power Consumption Level, Wearable Phone Holder Provides a Stylish Alternative to Carrying the Phone