Made of steel, the Omni Track® Office Storage Solutions by Hafele are available in different configurations. The Paper Tray is for 8-1/2" x 11" letter size paper. The Pencil Tray is used for writing utensils as well as other small items. The Small Tray is used for paper clips and other small items, while the Upright Tray is used for pens, pencils and other small items. The File Hanger fits 8-1/2" x 11" letter size hanging file folders; and a second file hanger can be added on the front for more storage.