Turn your iPhone 4S into a black monolith - great for when you want a sleek minimal look. This kit comes with a shiny black plastic back and two basic screwdrivers (one pentalobe, one phillips - use whichever your phone has) to remove the back and replace it.
Replacing the back of an iPhone is a 5 minute project. Simply remove the two screws next to the dock connector, slide the old back off, and slide the new one on. Replace the two screws and you're done! This is one of the easiest mods you can do to your cellphone.