1U chassis, Support WIO/Proprietary motherboard size up to 12.3" x 13", 4 x 3.5" hot-swap SAS3/SATA drive bay SAS or enterprise SATA HDD only recommended, 4-port 1U SAS3 12Gbps Hybrid backplane, support up to 4x 3.5-inch, SAS3/SATA3/NVMe Storage Devices, 1U 600W platinum efficiency multiple output power supply w/PMBus, 2 full-height & full-length expansion slot(s) , 1 low-profile expansion slot(s), 4 x 40x56mm counter-rotation PWM fan(s), Optional 2 x fans for AOC cooling.