The folks over at EFO are at it again, this time they’ve got something of interest for you iPhone 4 owners out there who want more battery life.

The sleek power pack snaps inconspicuously onto the back of your iPhone, adding only a few millimeters of thickness, but more than doubling the battery runtime. If prioritizes consumption, pulling power from the Power Pack first, maximizing the iPhone’s internal battery.

 

     

 

Specifications :

• Battery type : Lithium-ion battery

• Weight : 74g

• Product compatibility : iPhone 4

• Standby time : up to 390 hours

• Talk time : up to 6.5 hours

• Internet use : up to 6.5 hours on 4G and up to 8 hours on Wi-Fi

• Audio play : up to 31 hours

• Video play : up to 9 hours

Video Demonstration : http://www.youtube.com/watch?v=hGkBeObhaGE

Product Link : http://efo.buy-lowest.com/mobile-c-88/iphone-4-external-power-pack-p-282

Price : US$28