Compatible: iPod classic, nano, touch, iPhone, iPhone 3G/3GS
Ivyskin Zappak Universal Battery Backup
Interesting more because of its price than its form factor, Ivyskin's new Zappak ($50) is a 3000mAh battery in a rectangular plastic and metal enclosure that sits just inside the footprint of an iPhone 3G or 3GS. The plastic houses a pop-out USB cable that can be used to recharge the battery, plus twin USB ports on the bottom that can be connected to self-supplied USB-to-iPod cables to recharge two devices at once. A set of red lights on the side flash to indicate charging, and can be set to display the remaining power of the battery by pressing a flush-mounted button next to the USB ports. Less than thrilling: Zappak puts out a high-pitched squeal when it's charging. Black, red, pink, and blue versions are available.