Wall filing system mounts easily and securely to any flat vertical surface. Expansion of this modular file is as simple as attaching the desired number of add-on pockets to each basic pocket. Includes all necessary hardware and mounting materials. Space required: 16" wide x 17" high. Contains one basic pocket and three add-on pockets. Makes four compartments. Includes Deluxe Hot File Labeling System to add functionality. One easy-to-apply label holder packet included with each pocket. Accommodates material up to 12-1/2" wide.