Black High-Gloss Cruzer Argyle Flexible TPU Cover Skin Phone Case for the HTC ThunderBolt ADR6400 Keep your HTC ThunderBolt ADR6400 safe and protected in style. Slip your HTC ThunderBolt ADR6400 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