Great for switchboards, customer service, sales departments, mailrooms and warehouses Expand the system with extension modules and panel sleeves (sold separately) . Wall system includes a gray wall bracket, 10 letter-size panel sleeves (20 viewing sides) with rugged gray frames and wall mounting hardware. Expands by adding multiple wall systems side by side. Sherpa Reference Systems & Catalog Racks part of a large selection of office supplies. Sherpa (R) Wall Reference System, Gray is one of many Reference Systems available through Office Depot. Made by Sherpa.