LG Motion 4G: External battery cases?

I know the iPhones and Samsung Galaxy S3s have external battery cases, like the Mophie Juice Pack (iPhone) that doubles the use time of their phone.

Is there any known CASES that can do this for LG Motion?

Yes course like the Onite.
Onite 2x 1800mAh Li-ion Battery for LG Motion 4G MS770 (MetroPCS.) / LG Optimus L7 P700, with Charger

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