Middle Atlantic MRK-4042 The MRK-4042 MRK Series 19" Gang-able Enclosure from Middle Atlantic is a fully welded steel rack with 40U capacity and a depth of 42 inches. Its steel frame and 1/8 inches thick structural-steel internal braces provide a weight capacity of up to 2500 lbs. This enclosure is also seismic certified to protect up to 1000 lbs of essential equipment when used in conjunction with MRK-Z4 brackets. This rack comes standard with a rear door, (2) pairs of 11-gauge threaded 10-32 rack rails with EIA spacing and labeled rack-space increments. Electrical knockouts on the top and bottom of the rear panel can easily be removed to pass cables. The configurable open top also includes a UHF/VHF knockout. This enclosure is gang-able, allowing you to expand your system at will by adding additional cabinets. The rack can also be customized with a number of separately available accessories to meet your exact needs.