Expandable folder with poly-prongs. A modern alternative for traditional lever arch files. It stores up to 800 sheets of paper (twice as much as a standard lever arch file). The Zero-Max system, with its expandable spine, can adjust according to the number of documents inside. In case of storing few sheets, the file retains its narrow spine, i.e. does not create ?dead space?. The grey folder is acid-free. Made of recycled materials. Suitable for storing documents in sheet protectors.