The Fixed Heavy Duty Vented Rack Shelf has adjustable rails and can be installed in 19” server racks and cabinets with square, round, or threaded holes. This 28" rack shelf can rack mount server equipment weighing up to 900 lbs, including large printers, tower servers, and UPS towers, and has an adjustable mounting depth from 15” - 31.5”. The vented rack shelf itself occupies 1U of space, and its support brackets take up an additional 1U of space. The Fixed Heavy Duty Rack Shelf can fit to 4 Post racks, and can also be center or flush mounted to 2 Post racks. The rack shelf is made from 1/8" steel and includes all necessary installation hardware.