In many firms, stock clerks and order fillers use hand-held scanners connected to computers to keep inventories up to date. In retail stores, stock clerks bring merchandise to the sales floor and stock shelves and racks. In stockrooms and warehouses, stock clerks store materials in bins, on floors, or on shelves. Instead of putting the merchandise on the sales floor or on shelves, order fillers take customers' orders and either hold the merchandise until the customers can pick it up or send it to them.