XTremeMac (http://www.xtrememac.com) has announced four new iPhone 4S cases. They’re available for purchase now.

The US$29.99 Tuffwrap Shift is a soft TPU form-fitting case. It features an exclusively formulated material that changes the case color when activated with body heat or other heat sources. The soft case conforms to the iPhone 4S and is available in these flavors: blue that changes to white, pink to white, purple to blue, grey to white, green to white and orange to yellow.

The $29.99 Microshield is an impact-resistant, hard plastic case that features a smooth, matte surface allowing users to slide the phone in and out of pockets. It offers full access to all ports, controls and connectors and sports a metallic finish. The Microshield is available in several Metallic trend colors: Slate Blue, Deep Plum, Bronze, Pearl White or Graphite.

The $24.99 Microshield Style is a hard plastic, faux leather wrapped case. It’s available in high fashion faux texture trends such as Black/Silver or Brown/Black Snakeskin and Black Ostrich prints.

The $24.99 Microshield Layers case is a two-piece construction of a hard plastic outside and soft inner case delivering two layers of protection. It comes with multiple interchangeable inner cases to be used alone or with the included hard plastic shell. The Microshield Layers is available in a white outer shell with solid royal blue and mixed multi-color red/blue/yellow inner cases or in a black outer shell with a solid bubble gum pink and mixed multi-colored peacock blue/bubble gum pink/lime green inner cases.