Windows Server 2003, Standard Edition is the ideal multipurpose network operating system for the everyday needs of organizations of all sizes - especially small businesses and workgroups. Designed for small organizations and departmental use, Windows Server 2003, Standard Edition delivers intelligent file and printer sharing, secure Internet connectivity, centralized desktop application deployment, and Web solutions that connect employees, partners, and customers. Windows Server 2003, Standard Edition provides high levels of dependability, scalability, and security. Windows Server 2003, Standard Edition takes the best of Windows 2000 Server technology and makes it easier to deploy, manage, and use. The result: a highly productive operating system that is secure, reliable, and ready to use "out-of-the box", with features that provide robust availability and scalability.

This adds 5 Clients to an exsisting Windows 2003 Server.  This item is for Windows Server 2003 Standard (not Small Business Server 2003). This is an add-on license - you must currently own the software to use this license