High Quality Material and Spiral Ring Design: High quality polypropylene (PP) material (non-toxic and non-radiative), durable, fashionable, waterproof, not easy to break and deform, and can withstand repeated wear and tear. The durable spiral binding allows you to place your sheet music flat on a stand, with the covers at a 180-degree angle.The folder will not close by itself while on a music stand.Let you more convient and focus on playing instrument. .Center hollow design: Humanized design, use convenience. There is no barrier between the middle diaphragms, you can modify the internal content at will, the open pocket design allows you to easily modify your score or document files, very considerate and convenient. .Double Side Clear Documents Organization: Suitable for A4 size, both sides can be used on both sides, 60 sheets can be placed on 30 pages. Large capacity to store many A4 standard music papers or other documents. Better classification and easier searching, prevent splashing, protect your files and pictures from falling out, and avoid confusing files.