Merlin iPhone4 Case with Battery - Built-in Speaker.
The Merlin iPhone Case with battery is the ideal backup battery with speaker for your iPhone 4/4S, battery pack allows you to charge your iPhone on the go.
You can also use the iPhone4/4S while connected to the Merlin battery pack. In that case your iPhone will have far greater use time.
Battery+Speaker: Double your iPhone standby and talk time plus get an astoundingly loud and clear speaker. Enjoy movies, games and music on your iPhone 4/4S like never before.
Charge and Sync: Charge and sync your iPhone to iTunes without removing it from the battery pack air.
Fully Protected: The battery pack air not only adds battery life, it is a protective form-fitting case with an ultra-thin, light-weight, low-profile design.