External backup Battery Case charger for iphone 3GS 3G

Features:

1.  Provides you twice the battery life of the iPhone 3G/3Gs and its considerate human
engineering design on the hard-shell case offers you full protection of iPhone 3G/3Gs
2. Designed by China top class University, Tsinghua University. Ultra thin in designing
(the thinnest protective battery) and excellent in workmanship, which can perfect match
your Iphone and your iPhone can be more perfect with the Power pack
3. Can solve the problem that other products may bring some frozen or unsteady to
iPhopne 3G/3Gsdue to the electromagnetic interference while answering the call when
charging. Power Bank is theonly protective battery that can remove the interference
 from Iphone and even the Power pack wont stop charging for Iphone while answering
the call and the calling quality always be smooth  and sound.
4. Adopt ATL Polymer Li-ion battery to ensure the best quality and security
5. Charing and transmission can work synchronously..Power Pack never need to take off
from your iPhone and you can use the same cable to achieve both charging and date transmission.
6. Various protection like short circus protection, over charging protection, over discharge
protection and temperature protection can ensure your iPhone absolutely safe and sound

Specification:

iPhone 3GS
Standby time:Up to 270 hours
Talk Time: Up to 4.5 hours on 3Gs
Internet Use: Up to 4.5 hours on 3Gs, Up to 8 hours on Wi-Fi
Audio Playback:: Up to 27 hours
Video Playback:Up to 9 hours
 
iPhone 3G
Standby time:Up to 271 hours
Talk Time: Up to 4.5 hours on 3G
Internet Use: Up to 4.5 hours on 3G, Up to 5.4 hours on Wi-Fi
Audio Playback; Up to 20hours
Video Playback:Up to 6 hours
 
Cell capacity:1300mAh/3.7V
Cell type: Polymer Lithium-ion battery
Output voltage:5V
Output current:700mA
Cycle life:500 times