Perfect Size: These paper storage boxes are spacious, measuring 31x22x5cm. Each box has a generous capacity to hold up to 500 sheets of A4 paper, for a total of 2000 sheets with this four-piece set. Durable Material: Made of high-quality and durable PP plastic, these plastic storage boxes with locking lids for classroom organization/storage are BPA-free, dust- and moisture-resistant, and can withstand weight without deformation. Designed with a semi-transparent structure, they allow you to quickly locate desired items without having to open the lid. Airtight Closures: The plastic storage boxes with lids feature a snap-lock closure system that keeps the latch securely locked, preventing items from being lost or scattered. They are therefore perfect for storing board games. Multiple Use: These plastic storage containers are perfect for organizing items at home, in the office, or at school. They can hold 8.5" x 11" letters, folders, clipboards, documents, and other office supplies. They can also be used to store craft items such as photos, stamps, markers, scissors, and notebooks, making them ideal for school supplies or travel. Stackable Design: The four boxes can be stacked, making them easy to transport and save space. When not in use, the lids can be removed, and the four boxes can be nested inside each other for even more compact storage.