We received the Third Rail System for review and they’ve really got a unique iPhone accessory here. In a nutshell it’s a very thin case with a removable battery for extra juice when you need it. The battery’s removable aspect is what makes it unique- you just pop it on or off as needed and the remaining case is ultra-thin. If you keep your phone in a case and need an occasional battery boost- this is perfect for you. Check out our video review:
The other big advantage of this case for the iPhone 4 and 4S is that the battery can be used to charge ANY USB device. There’s a USB out plug that lets you do this. This means that you can actually charge your iPhone without the case as well as any device you have on hand that uses USB- bluetooth headsets, iPods, other phones and more.
The case (and battery) both use a micro-USB out plug to charge via USB and since the phone does actually dock into the case, you can sync and charge your phone with the case on. The battery has a 1250 mAh capacity which is almost enough to fully charge your iPhone from empty (the iPhone is 1450 mAh) and you can stack the batteries (on or off the case) to create a power brick of sorts. The Third Rail System Case sells for under $90 on Amazon and extra batteries are about $35.