Key Features 1. 4x 2.5" Hot-swap SAS3/SATA3 HDDs 2. Overheat LED indication 3. Drive Activity/Failure LED 4. 1x 5.25" Drive Bay Enclosure 5. 4x SATA HDD Connectors, up to 12Gbs support 6. 4cm Cooling Fan 12.5K RPM 16 CFM