The SR42BMDEXPNDNR3 offers 36-inch (927-millimeter) depth opposed to the standard 42 inchs (1050 millimeters).The SR42BMDEXPNDNR3 houses 3,500 pounds (1588 kilograms) of standard 19-inch rack equipment in 42U. It is an expansion model that comes without sides, doors or roof. The front and rear pairs of vertical rails have square mounting holes that are adjustable in quarter-inch increments from four to 28.75 inches. Adjustment is quick and an easy-view depth index ensures consistent rail placement without requiring time-consuming measurements. Each rack space within the enclosure is numbered for ready reference and supports tool-less button-mount 0U installation of up to four compatible PDUs and cable managers.All components of the SR42BMDEXPNDNR3 are grounded to the enclosure frame. Front and rear threaded grounding points are provided for connection to the facility earth ground.To simplify deployment, the SR42BMDEXPNDNR3 comes with preinstalled three-inch casters that enable it to be easily maneuvered into the desired location, where it can be secured by adjusting the preinstalled levelers. Note: The casters are intended for minor position adjustments and are not designed for moving the enclosure over long distances.