The product is a vintage 1985-1998 Microsoft Windows NT Workstation Operating System version 4.0, complete with a CD key. It is specifically designed for Microsoft Windows NT and Windows operating systems, with English language support. The item is a standard license category, sourced from the United States, and suitable for use on one device. This collectible operating system offers a glimpse into the technology of the past and is ideal for those interested in retro computing or for developers looking to support legacy systems.