With this battery case, it is easy to power your iPhone4/4S anywhere anytime. Offers you the convenience of a fully protective,  hard-shell case with virtually twice the battery life of the iPhone alone. Thin, light weight, low-profile design

Features:

Totally cover and protect your iphone4/4S from slipping
Thinnest and lightest
Specially designed camera hole for eliminate flash glare
Quick charge(5V, 0.5A)- (5V, 0.8A). Same as the original power adapter
Soft cover- easy to push the on/off button of your iPhone4/4S

Specifications:

Model: rechargeable external battery case for iPhone4/4S
Capacity: 2000mAh
Input: 5V, 0.5A
Output: 5V, 0.8A
Dimensions: 126x 63 x 16mm
Weight: 62g
Package size: 213 x 110 x 26mm
Package contains:
1 x External Battery Case for iPhone 4/4S

iphone 4 external battery