Features 4U rack mount design. 24x hot-swappable SATA (II or III) / SAS 6G drive bays. Six internal SFF-8087 Mini SAS connectors support up to twenty-four 3.5 or 2.5 in. SATA (II or III) or SAS 6G hard drives. Hot-swappable HDD tray with special designed power-off and lock mechanism. 24 x 3.5 in. hot-swappable drive bays. Ball-bearing cooling fans for better ventilation. RoHS Compliant. Support EEB (12 x 13 in.), CEB(12 x 10.5 in.), ATX (12 x 9.6 in.), Micro ATX (9.6 x 9.6 in.), ITX (6.7 x 6.7 in.) motherboard. Two front USB ports. 4pin Molex Power Adapter Option (not included) - Sata power to 4 pin molex power adapter. Optional part (not included) - OS drive mounting bracket. Specifications Drive Bay - 24 x hot-swappable SATA (II or III) / SAS 6G drive bays. Cooling Fan - 4 x 80 mm. middle fans wall, 2 x 80 mm. 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 - Two front accessible USB ports, six internal SFF-8087 Mini SAS connectors.