[custom:mwc15]Part of the fun of an event such as Mobile World Congress is trawling the halls and seeing weird and wonderful devices you might never normally come across. And that's exactly what happened when we stumbled across Innos, a Chinese smartphone maker you've probably never heard of. Its flagship Android device is this, the D6000, and it has a pretty spectacular signature feature: It has a 6000mAh battery.

Specs wise we're looking at a decent enough, but still mid-ish range device. Snapdragon 600 CPU, 5.2-inch 1080p display, 16GB of internal storage, 2GB of RAM but with a solid sounding 16MP rear camera with dual LED flash. But this phone, and the marketing around it, is all about that battery. Or rather, batteries.

When you pull the back cover off the D6000 you see a removable battery. But this is only half the tale as when you pull it out the phone will stay on. That's because it has an internal, sealed battery as well. The two work together, draining and charging at the same time, so you're never just using one battery to empty then starting to use the other. Of course, it also means so long as the internal battery has some charge you can swap out the removable one to keep on trucking even longer.

So, while we'll never likely see one in western markets it's always pretty cool to see interesting ideas being tried out. It's not what you'd call slim, but at the same time it's not as if you're carrying a car battery around, either.

Innos D6000