The saxophone bags are made of imported Taiwan nylon 600D fabric, which is waterproof and wear-resistant. The upper part of the lid is made of memory foam. You may need to press it lightly to cover it for the first time. Please don't worry, this is normal, just press it lightly to close the zipper. It will not hurt the instrument, and it will be set after using the cover a few times. It will fit just like the original factory. This is to prevent the instrument from shaking in the case and hitting the keys. Like the kind that can be closed directly, the inner tube must be large and cannot protect the instrument at all. Parents, please keep your eyes open~