First Look: XtremeMac Tuffwrap Shift for iPhone 4/4S
Without further inspection, XtremeMac's Tuffwrap Shift ($30) for iPhone 4/4S looks like any standard rubber iPhone 4/4S case: available in a variety of colors, it's flexible enough to be easy to take on and off of a device, but has enough structure to maintain its shape. There's coverage for the Sleep/Wake buttons, but all of the other ports and buttons are exposed. What sets Tuffwrap Shift apart is the special rubber the company uses: it's heat sensitive and changes color based on touch, an effect that is most pronounced after holding the case for a few minutes. It then fades back to the standard color after being left alone.