Say goodbye to chunky and clumpy additions to your iPhone 4/4S that can make it almost impossible for it to fit in your back pocket. 
The MiLi® Power Pack 4 is the world’s longest lasting iPhone 4/4S case with battery charger that triples the life of your battery. With it's sleek form fitting design, it will also protect you iPhone 4/4S from scratches. 

Features

• Worlds largest capacity external battery
• Triples the life of the iPhone 4/4S
• sleek, form fitting design that protects your iPhone 4 from scratches
• Color : Black

Technical Details:

• Capacity: 3000mAh
• Input: DC5V/500mAh
• Output: DC5V/500mAh
• Product compatibility: iphone 4
• Standby time: Up to 675 hrs
• Talk time: Up to 11.25 hrs on 3G
• Internet Use: Up to 11.25 hours on 3G
• Up to 19.95 hours on Wi-Fi
• Audio play: Up to 87.5 hrs
• Video play: Up to 22.5 hrs
• Self-charging time: 4.5 hrs