Norco 3U Rack Mount 3 x 5.25-Inch Drive Bay, 9 x 3.5-Inch Drive Bays Server Chassis RPC-370 3U rack mount design, meets EIARS-310C standard. 3 x 5.25" drive bays, 9 x 3.5" drive bays Support EEB (12"x13"), CEB(12"x10.5"), ATX (12"x9.6"), Micro ATX (9.6" x 9.6"), Mini ITX (6.7" x 6.7") motherboard 4 x 80mm ball bearing middle fans wall, 2x80mm optional rear fans for better ventilation Two front accessible USB ports