Exogear's Exolife is probably the slimmest battery case for the iPhone 4 on the market, it's sleek, slim, lightweight and it's just the case that you're looking for, or is it? While the Exolife has a very thin profile for a battery case, it does not live up to it's main purpose which is doubling your iPhone 4's battery life. After many tests of charging and discharging the Exolife, I could only get it to charge my iPhone 4 to about 70%, and that's without even using my iPhone while it's charging! Not good enough Exogear. I was expecting to get at least a full charge out of the Exolife after running the battery for more than five times however I only managed to get about 70%. If you want to keep using your iPhone 4 while your Exolife charges it, and believe me you will, then you will be lucky to even get a 50% charge while using your iPhone 4.
The Exolife uses a semi-translucent plastic bumper that you install on your iPhone 4 to secure it to the Exolife Battery. This bumper case has deep cutouts for the volume, silent and power buttons making them very hard to reach with your fingers. To get to those buttons you really got to fit your nails thru the cutout of the bumper and that is a bad design flaw. If you have any side skins on your metal band, you will need to take them off in order to use the Exolife with it's bumper case. The Exolife does not offer much protection to your iPhone 4 except for the back and sides. There is 0 lay on the table design with this case, so your whole front glass screen isn't protected at all. While the Exolife was charging my iPhone 4, it's bottom part near the battery light indicator got noticeably warm throughout the whole time it was charging. Something to be aware of if you are sensitive.
On the back of the Exolife you will find a blue battery indicator light that will tell you the remaining battery charge on the Exolife by pressing a button on the bottom side, which also powers on and off the Exolife's battery. Charging the Exolife is very easy and is done by a USB cable. You can sync and charge both your iPhone 4 and your Exolife's battery via the supplied USB cable, though you will charge your Exolife much faster without your iPhone 4 attached to it. The Exolife does make your iPhone 4 a bit longer due to the on board battery and how slim it is. I actually think that even with the Exolife Battery Case, holding it was comfortable due to it's slim profile and rounder back. The Exolife comes in both a glossy black or white finishes with only a USB cable. I cannot recommend the Exolife at it's current price tag and with a false battery advertisement. Price $89.95.