The Mobius is a solar powered rechargeable battery case for iPhone 4 and iPhone 4S. With one hour of sunlight, the Mobius will yield 25 minutes of talk time. There is an option to shut off the dump charge feature to the iPhone, allowing your case to charge and stores its own battery power. It also comes with a USB connection to recharge the lithium-ion battery pack with a laptop. You can even sync it with iTunes. The solar charge indicator shows when it is charging and the battery indicator shows the level of power available.