iPhone 4 GSM Only The MicroShell for iPhone 4 GSM Only provides the ultimate in low-profile polycarbonate shell protection. We call it the MicroShell because it's less than 1mm in thickness-amazingly thin. The clear version is unobtrusive and ideal for showing off the iPhone. The MicroShell is also available in multiple colors, and is designed to appeal to the minimalist who is primarily looking for scratch protection on the back and sides and of their iPhone but doesn't want to add too much thickness. Overall, the MicroShell is an ideal case for anyone who wants to keep their iPhone thin while carrying it in a pocket or inside another fabric case.