A Backup Appliance (also known as a "data backup appliance") is an all-in-one product that provides all of the essential components of a backup system architecture that are required to build a complete backup solution, bundled into a single appliance. A backup appliance is usually designed for and sold to IT departments for small and medium-sized businesses. A backup appliance includes within it backup software (which provides the backup manager), and backup storage. A backup appliance usually includes (or provides) additional backup client software, which is for installation on the computers that are to be backed up (the backup clients ) and do not have backup agents pre-installed.