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 is a little harder than silicone, but it is more expensive, more resistant to dirt, oil, water, dust, and very very durable.