The OffGRID PRO is a backup battery case with a slim profile made from polycarbonate. It is design to give your iPhone 4/4S a slim fit look. The OffGRID PRO comes with a set of two interchangeable and rechargeable lithium-ion batteries with 1600mAh of charging capacity each, totaling 3200mAh and 3.7V. You are also provided [...]