If you look at the front of the Olive FrvrOn mobile phone from India, it appears to be like any other low-cost handset. But once the back battery cover is off, you'll notice it's special. Aside from a regular rechargeable cell, the FrvrOn has a slot for a AAA battery. Should you find yourself out of juice without your power adapter, just head over to a convenience store to pick up a pack of Energizers for extra talk time.
At about $37, it's also incredibly cheap. Its other specifications are listed in the image above. Most of us probably won't need something like this, but if you do, you need to be in India to get one.