Unlike most battery packs, PowerSkin isn’t a two-piece slider-style case. Instead, it’s one unit with a hard plastic back and pliable silicone rubber edges along the left, right, and top. Those edges have enough give that inserting and removing the iPhone 4 is very easy. One of the benefits of the rubber case is that you’ll actually have button coverage: the Sleep/Wake button and volume buttons are both protected, but still…
