Designed for Apple Airpods 1 & Airpods 2 charging case,because of its light and thin, it needs to adjust the top to fit 100% at first use. Precision molded for great fit. Protects your AirPods against bumps and drops. Made of durable TPU, a little hard but smooth,protect your Airpods charging case from scratch,dust and dirty. Easy to install and remove,don’t need to take out of the case when you charging. TPU (Thermoplastic polyurethanes) is named thermoplastic polyurethane elastomer rubber. Mainly divided into polyester type and polyether type, it has a wide hardness range (60HA-85HD), wear resistance, oil resistance, transparency and elasticity.