Thermoplastic polyurethane (TPU) phone cases are a protective case made from polyurethane plastic. These cases offer some protection against impact as well as a surface that resists liquids, grease and abrasion.
Commercially available TPU is a hybrid of hard plastic and flexible silicone. It has a rubber-like elasticity that allows it to be stretched to fit snugly around phones. In addition to protecting phones from spills, low-level impacts and skin oil, these cases also resist the accumulation of lint when kept in a pocket. They also do not have the potential to scratch phones as some polycarbonate plastic cases do.