Incipio iPhone 4 4S offGRID Backup Battery Case - 1450mAh - 1 Pack - Carrying Case - Retail Packaging

The offGRID Backup Battery Case for iPhone 4 is the thinnest, lightest and most efficient iPhone backup battery case available. This case has an ultra thin rechargeable battery built inside of a snug fitting, low-profile protective case that promises to double the battery life of the iPhone 4. The power /status button allows the user to determine the charge level and status quickly ,with just one soft touch button and a series of blue lights

Owner Reviews, Ratings, Comments and Criticism
Over the past year or two, I've owned the Incipio Offgrid, Mophie Juice Pack Air, and Tekkeon My Power. They all 3 work as advertised. I mean, how hard is it really to make a case with a battery in it that charges the phone. The hard part is making one that looks halfway decent. The Incipio Offgrid is hands down a much better looking product than the other two. It barely even looks like a battery case other than the little extra bit that plugs into the dock connector.The Offgrid will charge up my fully drained iPhone 4s to about 65%. While there are cases out there (juice Pack Air Plus comes to mind) that claim to offer a full charge, they are huge. The Offgrid has 4 very subtle blue LEDs that indicate charge capacity. You don't even know they are there because they only light up for a few seconds if you press the power button. The case is smooth glossy black so you don't have to worry about the rubbery coating flaking off like so many other cases.EDIT (11-18-11):One thing I have since learned since originally writing this review is that due to the way the case covers the microphone, it causes an echo that can only be heard by the person you are talking to. I haven't seen this problem with any of the other battery cases I've owned. I email, text, and use safari way more than I talk on the phone, so it's not a huge deal for me. If you talk on the phone a lot, this case may not be for you. Have to knock it down a couple of stars since it renders the voice portion of the phone useless. Fix that, and I'd give it 5 stars in a heartbeat.As far as the question about the flash, I have no idea because I try not to use the flash because it makes pictures look bad. Due to the thickness of the case around one side of the camera opening, I wouldn't be surprised if blocked the flash a little.