Shirodhara Archan Designs Case for Iphone4 /4s Keep your iPhone 4/4s safe and protected in style. Slip your iPhone 4/4s in to add color. TPU, also known as thermoplastic polyurethane, is more cut and tear resistant than rubber. It is abrasion resistant, and has a high degree of transparency. This skin is more stiff than silicone skins, but remains flexible. Applicaton and removal are easy. Shock absorbent, shatterproof, and anti-scratch material