Get organized with an expandable pocket file system that allows you customize your wall filing system. The interlocking design allows you to add pockets as your organization needs grow. Each pocket holds papers, envelopes, and electronic media. The items are easy to spot and add or remove from the pockets. Mounting hardware included. Crafted from sturdy, clear plastic that is designed to be tough enough for active environments. Add-On Pocket. Hanging File Systems Type: Expandable Single Pocket; For File Size: Letter; Overall Height: 7"; Width: 13".