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