Specifications:

Extend your surf time talk time and tune time with PowerDuo Reserve the auto charger / wall charger combo with a detachable rechargeable battery for iPod and iPhone. Use PowerJolt Reserve in your car's 12 V DC power outlet. Plug PowerBlock Reserve into a wall outlet. At the same time it's powering your iPhone or iPod the charger is juicing up its detachable Reserve battery pack. When you're ready to go slip the Reserve battery pack into your pocket and you're ready for anything. The Reserve battery snaps into your player's dock connector adding hours of play time on your iPod or iPhone. No more worrying about battery life and no more lugging your charger along.