This enclosure is 1200 mm deep (47.25") compared to the standard 1070 mm deep (42"). This extra depth allows for high density equipment installations. It allows extra space for moving the cable management back as well as providing space for mounted equipment that has hot-swap, removeable power supplies out the back of the enclosure. It is also 750 mm wide (29.5") compared to the standard 600 mm wide (23.6"). This extra width allows for high density equipment installations. It allows cable management and PDU mounting off to the sides of the rack in order to keep these items out of the airflow for proper cooling. All features from the standard SmartRacks carry over to these wide racks to allow cross usage of accessories.