This ability comes at a slight cost of around £60 ($100) and
it adds another 1mm of bulk. The Juice pack comes with a simple toggle
button that allows for standby and charging mode so you only ever use
the juice pack when you wish to use it.
Furthermore, you can charge and sync the iPhone to iTunes without
having to remove the Juice Pack by using the included USB cable. In
addition, the Juice Pack provides a rather comfortable protective
rubberized design.
Just to make sure you know how much juice is left in the Juice Pack
there is an integrated LED status indicator on the bottom that tells
you exactly how much juice is left at a simple push of a button.
The case doesn't just help charge your iPhone when it's low on juice
but the case is designed in such a way that it acts as a virtual
speaker box, redirecting sound from the bottom of the iPhone 4 to the
front creating a richer, fuller and overall better sound quality.