Pendaflex SureHook Pocket Reinforced Box Files, 3" Expansion, Letter Size, Blue, Pack Of 25 - Maintain a well-organized file system with help from these Pendaflex SureHook box files. Reinforced with a pressboard insert and polylaminate in high-stress areas, these Pendaflex hanging folders are made to hold bulky projects. It's easy to categorize these files for quick referencing later.