Sometimes, perhaps often, you're faced with the dilemma of finding yourself far from a power source and a drained out iPhone. We know you probably keep a car charger…in your car. But what about the times when you're on the go and you need to call or get online? Perhaps it's time to add an external boost to your tech supplies...
Mophie Juice Pack Air
Not only does the Mophie protect the phone, but we love how "high quality" this case+battery looks and feels. The ultra thin case is almost invisible, it doesn't add too much to the iPhone 4's exterior. It will add up to six hours of talk time and whooping 270 hours of stand by, so gab and browse away. The soft touch back case offers full protection against bump and scratches while looking sharp.
Logic3 Power Sleeve
The PowerSleeve combines a built-in rechargeable Li-Polymer Battery pack for your iPhone 4, adding extra hours of battery life while talking or listening to music (7 hours talk time / 40 hours music playback / Video 10 hours). We really like the slim-line design and inner soft suede finish are designed to match and protect both the style and sophistication of the iPhone4. The battery is a 1600mAh and has 4 LEDs for power level indication.
Mili Power Spring
This is the thinnest battery case for the iPhone 4. We love the double battery life and the added protection. The status indicator will tell you how are you doing battery wise. With a great capacity of 2000mAh and output of 5v you can enjoy of 19 hours of audio playback and 230 hours of stand by. We also like the fast charging times to get the battery full after depletion.