Constructed of high-grade 6061-T6 aluminum. Self-squaring and self-supporting. Has 3" x 1 1/4" channels. Features a 5/8", 5/8", 1/2" universal mounting hole pattern. Includes 24 cross-recessed black panel mounting screws, 12-24 x 1/2" long. Add Premier Cable Managers (RM122–RM125, RM128–RM133) for additional cable management. This EIA standard 19" distribution rack is constructed of high-strength aluminum for lightweight strength; the rack supports up to 1000 pounds; and has excellent grounding characteristics. The rack is easy to assemble, and it's self-squaring and self-supporting. And to accommodate your non-rackmountable equipment, shelves are available for our Premier Aluminum Distribution Racks. Like our racks, these shelves are sturdily constructed to withstand hard use. Each single shelf supports up to 50 pounds (22.7 kg); each double shelf supports up to 125 pounds (56.7 kg). Choose from single- or double-sided shelves with or without vents.