For those road warrior who needs an iPhone with longer battery life, you can simply plug in the mophie Juice Pack and double up your normal use time. The battery pack also provides 4 light LEDs on the back of the Juice Pack. Simply press the test button and it will tell you how much power is left with the Juice Pack. The LED lights also indicate the charging status and the charging progress.

check out iPhonebuzz initial impression here

http://www.iphonebuzz.com/mophie-juice-pack-for-iphone-initial-impressions-182240.php