A 19-inch rack case is a housing designed to accommodate electronic equipment such as servers, audio gear, network devices, and other electronic components. The term "19-inch" refers to the standard width of the equipment, measured between the mounting holes on the front of the rack. This standard dimension of 19 inches (approximately 48.3 cm) allows equipment from various manufacturers to fit into the same rack case.

A rack case typically consists of a rectangular frame with mounting options on the front and rear in the form of slots, holes, or threads where the equipment can be secured. The standard height of a rack is measured in rack units or "U." One rack unit equals 1.75 inches (4.45 cm) in height. Therefore, a 2U rack case is, for example, 3.5 inches (8.89 cm) high.

The use of rack cases facilitates the management, organization, and maintenance of electronic equipment in professional environments such as data centers, server rooms, audio studios, and network installations. They allow users to efficiently mount, cool, and manage equipment, providing a standardized way to integrate different devices into a system.