The X-Power 1 might look like just an ordinary charging cable for your iPod or iPhone but hidden along that cable is a small battery. This inline battery is about the size of a AAA battery and can actually hold a charge on it’s own allowing you to charge up your device straight from the cable even if it’s not plugged in to a computer.
So we’re basically talking about a lithium ion backup battery combined with a charging cable. It totally makes sense to combine the two, especially since the battery doesn’t take up a whole lot of space on the cord. That’s one less thing to carry around. It costs $30 and comes in 6 inch, 20 inch, and 30 inch models in black or white. Sure the small battery isn’t going to give you as much juice as some of the larger power packs you see but if you’re carrying a cord around with you anyway, why not have a spare battery (especially since the iPhone/iPod batteries are non-removable.)
x-power1 via gadget review