Here at Energenie we know how annoying it is to run out of battery when you're on the go, now with the ChargeSleeve for iPhone 4 that no longer has to be a problem! As Energenie presents its iPhone 4 ChargeSleeve, this product slides on to the back of your iPhone and recharges it. It has a 1, 8 00mAh battery which allows for a full recharge of your iPhone. The product comes with a USB to MicroUSB cable to recharge your ChargeSleeve.