External Battery Case for iPhone 4/4s

Features:
Smart Battery (Optimized to lengthen your iPhone performance time; No more out of power dilemma during important phone conversations)
Full Body Coverage for iPhone4
Lightweight, thin design (Low profile)
Non slip comfort grip
Automatic tests function
High-quality Li-polymer Cell
Extended battery pack - 1900 mAh
ON/OFF Button for Optional Power Output Control
Four LED lights indicates the power level remaining the case (Each light represents 25% of remaining power)
Sleek, Low-Profile design; Rechargeable up to 1000 times
Size: 125*62*17.5mm
Specification:
Fully charged in 3 Hours
Battery type: Lithium-ion polymer battery (Way better than Lithium-ion batteries).
Output voltage: DC 5V
Output current: 1900 mAh
Output: 5V
OEM Version/Retail Gift Box Package, iPhone4 USB Cable included.