Key Features 1U chassis support for motherboard size 13.68" x 13" and ATX 12" x 10", E-ATX 12" x 13" 4 x 3.5" hot-swap SAS/SATA drive bay with SES2 SAS or enterprise SATA HDD only recommended 4-port 1U TQ backplane (W/ enclosure management), support up to 4x 3.5-inch SAS/SATA HDD 1U 600W platinum efficiency multiple output power supply w/PMBus 1 full-height & full-length expansion slot(s) (Riser Card Required) 4 x 4cm heavy duty counter-rotating with optimal fan(s) speed control Optional 2 x fan for PCI card cooling