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 model includes (2) pairs of Proliant cage-nut style rack rails. 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