The SR45UBDPWD is a DEEP and WIDE version of the standard 45U SmartRack. 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, removable power supplies out the back of the enclosure. 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.