The UNU DX Plus Protective Battery Case for the iPhone 4s / 4 retails for $60 and has a 2400mAh battery.
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The iBattz Mojo removable power card wallet retails for $39.00 and is available in black and white.
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The CalypsoPad is an Italian leather charging pad the retails for $39 and is a great place to set your iPhone 4 or 4s.
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The Aeris Rail an aluminum bumper case for the iPhone 4 / 4s it retails for $109.99at their website. The Rail is a screw less design aluminum bumper that is retained in place with a plastic bumper.
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The ARKHIIPO II case by ARK What retails for $29.00 and fits the iPhone 4 and 4s. 
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The ARKCANARY 2 and the ARKHIPPO 1 for the iPhone 4s/4. The ARKHIPPO 1 retails for $24 and the ARKCANSRY 2 for $19.
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The iBattz Mojo removable battery case for the iPhone 4/4S comes with 2 1500mAh lithium polymer batteries. The 2 batteries will allow you to use your iPhone for days without looking for a power outlet.
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