This "Crystal" edition iPhone 4/4s bumper, a.k.a. "CLEAVE", is an extension of the DRACO IV. To protect your iPhone 4/4s, polycarbonate is used as a base material. The bumper's surface is hard to help prevent scratches or dings, while the elastic inside the frame of the bumper is used for shock absorption. The CLEAVE weighs a very light 9 grams while keeping the same aesthetics and mechanics design materials of the DRACO IV. The amazing contours and curve lines of the CLEAVE is a masterpiece of craftsmanship with the ergonomics of engineering design.