Model No: i1200A --- Exclusive patent design product.

Specifications:

This juice bank is specially designed for iphone 3G/3GS with a ultra-thin,light-weight,low-profile characters and as a rechargeable external battery concealed inside of a protective form-fitting case for the iPhone 3G & iPhone 3GS.

It offers you the full protection of a hard-shell case while providing virtually twice the battery life of the iPhone alone;

From the design and build quality perspective, Anecoo Juice bank is truly top notch. The hard plastic shell is sturdy, it fits our iPhone 3G & 3GS, like a glove and it doesn't impede access to the volume rocker,power button and vibrate/ring switch.
On the bright side, there are four LED indicators on the rear that show the remaining power capacity with a simple button press,and activating the built-in battery is as simple as flipping a toggle switch on the unit's bottom.

Apple will never be perfect without our Juice Bank.

Function & characters:

Power check & LED indication
Power switch
Protective and powerful

It extends the time that you can use your iPhone 3GS or 3G in the way (additional hours):

iPhone 3GS:

Standby Time: Up to 270 hours 
Talking Time:   Up to 4.5 hours on 3GS 
Internet Use:     Up to 4.5 hours ON 3GS  I  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 270 hours 
Talking Time:   Up to 4.5 hours on 3GS 
Internet Use:     Up to 4.5 hours ON 3GS  I  Up to 8 hours on Wi-Fi
Audio Playback:Up to 20 hours
Video Playback: Up to 6 hours