Specifications: Drive Bay 20 x hot-swappable Mini-sas( or SATA/SAS) 6G drive bays 1* Slim 5.25' drive bay Cooling Fan 4 x 80mm middle fans wall, 2 x 80mm rear fans Switch Power ON/OFF x 1, System reset x 1 Indicator Power ON/OFF x 1, HDD x 1, NETWORK X 2 Connector 2x front accessible USB ports, 6x internal SFF-8087 Mini SAS connectors, 10x 4-pin redundant molex power connectors Motherboard Compatibility Support EEB (12'x13'), CEB(12'x10.5'), ATX (12'x9.6'), Micro ATX (9.6' x 9.6') Power Supply Options Standard ATX power supply, mini redundant power supply (H x W 5.91x3.39 inch) Dimensions ( W x D x H ) 19' x 25.5' x 7.0' (483mm x 650mm x 176mm) Packing Single box Weight (without hard drive) 18 kg/39.7 lb (NET) 21.2 kg/46.7 lb (GROSS) Environment Temperature 0/40 C, 32/104 F (Operating) -20/60 C, -4/140 F (Non-Operating) Relative Humidity 5% to 95%,non-condensing Features: 4U rackmount design 20x hot-swappable Mini-sas(or SATA/SAS) 6G drive bays 5x internal SFF-8087 Mini SAS connectors support up to 20x 3.5' or 2.5' SATA (I or II) or SAS hard drives; Backplanes are horizontal mounted for better ventilation LED indicators for power and activity on each HDD tray Support EEB (12'x13'), CEB(12'x10.5'), ATX (12'x9.6'), Micro ATX (9.6' x 9.6') motherboard RoHS Compliant Redundant 4-pin molex PSU connectors support redundant power supply 2x front USB ports Smooth border prevent lacerating your skin