Middle Atlantic’s SRS Sliding Rail System pulls out a full 19-inch to provide rear access to components with shallow depths. Measuring 19-inch deep, the unit locks closed with included hardware and includes a rear pair of 7 space 10-32 rack rail…. Sizes range from 8 to 20 spaces in 125 lb. (two slide) and 250 lb. (four slide) capacities, factory modified to the number of useable rackspaces you require. For effective cable management, an optional triple-hinged, full-width cable carrier is offered. For detailed millwork dimensions, consult the A&E Spec below. Brush Gasket fills unsightly gaps that may appear between the rack and custom millwork (requires a rough-in width of 19-5/8-inch)