TPU is a flexible plastic that's somewhere between silicone and hard plastic. This means smartphones made of this material seamlessly fit your phone. TPU is usually used for back covers, which protect the sides and back of your device. There are also TPU book cases and flip cases, which fully protect your smartphone. On top of that, TPU cases provide your smartphone with more grip. Make sure your phone stays intact even if you drop it by choosing a case with fall protection.