Top iPhone 4 and 4S extended battery cases - CNET Looking to boost the battery life of your iPhone 4 or 4S with a case that has a built -in battery? Here are some of your top choices for extended battery cases.
mophie juice pack air iPhone 4 Cases Rechargeable Battery Backup The mophie juice pack air® rechargeable battery pack iPhone 4 cases. ... run out of juice again on your iPhone 4/4S with this extended battery protective cover.