There are plenty of battery solutions for the iPhone, trying to answer a problem that we all know is true: how do you get around such an awful battery life? The latest contender, MiLi, believes it has the answer with the MiLi Power Skin that claims to be the thinnest battery skin out there.

The premise is simple. You charge the device, it then charges your iPhone throughout the day. When the MiLi Powerskin runs out, the iPhone resumes using its own battery, allowing you to go thin if you want.

Virtually identical to the Mophie juice pack air iPhone battery case, the MiLi Power Skin (yes it really is spelt and written like that) is, side-by-side, a fraction thinner but to be honest there isn't much in it.

The case, which splits in two halves to let you get your iPhone in, is made from a glossy plastic and available in black or white. Strangely you can choose an array of more exciting colours for the inside from green to orange, but of course once you've got your iPhone in the case, you won't be able to see it.

Whereas the Mophie offering uses a micro-USB, the MiLi Power Skin can be charged via its miniUSB cable and charging is as easy as plugging it in.

The side offers a four-light power meter that allows you to see how much juice you've got left and there is also an on/off button as well, although to be fair you'll probably want to dump the case as soon as its out of juice or you're not ready to charge it.