The 4U Computer Networking Rack is designed for applications that need large bundles of cables to cascade down either side or both sides of the rack rails and still maintain lockable security. A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is 19 inches (482.6 mm) wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.