Music Folder:Used to store sheet music, documents,etc,music folder,treble clef A4 paper with 30 compartments. Material: The inside pockets are non-slip and transparent with high quality polypropylene (PP). The spiral binding allows you to open the folder at a 180 degree angle for flat notes. Waterproof and thick pockets: the inside pockets are non-slip and transparent, and the concave convex technology can reduce the reflected light to ensure your treble clef does not get wet when practicing. Perfect for: Suitable for daily filing and storing A4 documents and less than A4, widely used in office, school and household. Works equally on piano, organ or performance synthesizer. Easy to use: choir and piano notes and other papers can be inserted. A standard display book that can be easily inserted into the sheet music or files and removed from them.