The PowerSkin uses an Xpal battery (Energizer's Energi To Go case is also "powered by Xpal") and features a 2,000 mAH battery. We checked with the company and it's supposed to work with both the iPhone 4 and 4S.
See pricing for Powerskin from Amazon.com.
January 30, 2012 9:34 AM PST
Photo by: Amazon
| Caption by: David Carnoy
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