The Mobility System from Third Rail is great. It offers a decent level of protection and has an optional battery attachment as well to charge your phone on the go. Unlike most other battery cases, this one uses an external battery rather than an internal battery. This is great because it allows you to have a nice sleek case, and a little extra power when you need it.
The battery hooks onto the back of the case by sliding into a locked position. You can also get an extra battery for it as well, so that you can travel with more batteries if you need to. Another great feature of this case is the fact that the battery doesn’t only charge iPhones. With the included USB adapter you can charge all your USB devices from this device.
All in all this is a very versatile option for someone who would like to have a little extra power for their portable devices. With the ability to charge on the go you never need to worry about running out of power again. Another nice thing about this product is the price. Most of these battery cases are over $100, but Mobility from Third Rail is only $89.99. That is a great value as it allows you to do so much.