Apple touts the iPhone 4 as having up to seven hours of talk time or enough power for 300 hours of standby. Both are pretty good marks…but everyone knows that real-world numbers are quite a bit lower. Spend a day roaming around town, checking in via Foursquare at each stop--or chatting via Beejive--and you’re lucky to make it through the afternoon before your iPhone battery takes a dirt nap. And once your iPhone’s battery has been around the block a few times, battery life becomes even more of a problem. Exogear’s Exolife iPhone case/external battery gives your depleted iPhone a new lease on life with an onboard 1500 mAh battery good for another seven hours of talk time.