1、Thick cardboard, durable, not easy to be deformed after long-term use, not easy to bend, no corners, to protect the internal files from damage 2、Strong clamping force, holding a large amount of paper still firmly, adding soft glue, strong clamping force without damaging the paper , Strong and not easy to slip off, high-quality hardware, not easy to rust 3、Data storage is neat and tidy, learning efficiency is doubled, documents are no longer scattered, and an indispensable storage folder for learning and office 4、Matches the size of the materials used in daily office and study, and can be easily put into most backpacks,bags 5、Can hold about 160 sheets of A4 paper, can be folded 360°, can be used as a writing board, unique design, multiple folding without leaving marks, can be held with one hand, easy to use