Music score holder: used to store music scores, documents, etc., music score holder, clef, A4 paper, with 30 slots. Material: The inner bag is non-slip and transparent, high-quality polypropylene (PP). Spiral binding allows the binder to be opened at a 180-degree angle for use with sheet music. Waterproof and Thick Pocket: The inner pocket is non-slip and transparent, and the concave-convex technology reduces reflected light, ensuring that your clef won't get wet when you practice. Scope of application: Suitable for daily filing and storage of documents of A4 size and smaller than A4, widely used in offices, schools and homes. Works equally well on piano, organ or playing synthesizer. Easy to use: choir and piano scores and other files can be inserted. A standard display book into which scores or documents can be easily inserted or removed.