The battery life of Apple’s iPhone 4 is more than any of its predecessors, but for many people, it’s still not enough. PowerSkin for iPhone 4 is a case-cum-battery that will offer lots more juice, as well as protect your valuable iPhone.
The PowerSkin’s 2100 mAH give you 50% more power in addition to the internal battery. The unit has an On/Off button at the bottom of the case, giving you the option to use the PowerSkin to recharge an exhausted internal battery, or to simply leave it off.
An important question is that how much more usage time do you get exactly with the PowerSkin? The only honest answer is that your mileage may vary as individual usage habits are so variable. However, if your usage pattern leaves you with an internal iPhone battery at roughly 20% after a day’s worth of calling and Internet, you recharge every night. Starting with a fully-charged iPhone and PowerSkin, you could get over two and one half days worth of usage before need to recharge.