Mi Li Powerpack 4 3000m Ah iPhone 4 Case with Worlds Longest Lasting Battery Charger Triple Your iPhone Charge The Mi Li Power Pack 4 is the worlds longest lasting iPhone 4 case with battery charger that triples the life of your battery. Say goodbye to chunky & clumpy additions to your iPhone 4 that can make it almost impossible for it to fit in your rear pocket. The Mi Li Power Pack 4s sleek form fitting design will also protect you iPhone 4 from scratches. It even prevents your iPhone 4 from the dreaded " Death Grip" reception problem.