Based on an extra-wide and extra-deep cabinet with two locking colocation compartments, the open rack enclosure supports hybrid equipment mounting. Upper and lower sets of mounting rails are convertible to support 21-inch ORV3 equipment or traditional 19" (48 cm) EIA equipment, allowing the rack to support either standard or a mixture of both, which is the default configuration. The open rack enclosure is available with or without a built-in ORV3 busbar and ORV3 power shelf.