A 9U rack refers to a rack enclosure that has a height of 9 rack units (U), with each rack unit measuring 1.75 inches (44.45 mm). Therefore, a 9U rack has a total height of 15.75 inches (400 mm). These racks are commonly used in data centers, audio/video setups, and telecom applications to house equipment such as servers, switches, and routers, allowing for organized storage, effective cooling, and ease of access to devices.
