Synology 4-Bay Extension RAID Storage for RS8, Hot-Swappable HDD design (RX410) Plug-n-use Minimizes Downtime Hot-swappable HDD design HDD Hibernation Managed from Synology Disk Station Manager 2.3 Internal HDD: 4x 3.5" SATA or 4x 2.5" SATA External HDD Interface: 1x eSATA