Built to support on-the-fly volume expansion and local backups, the DX517 5-Bay Expansion Enclosure from Synology adds an additional five 3.5"/2.5" SATA drive bays to their DS1819+, DS1817+, DS1817, DS1618+, DS1517+, DS1517, DS918+, DS718+, DS218+, and NVR1218. Its drive bays are hot-swappable and screwless, and included is an AC power cord, an accessory pack, and an eSATA expansion cable. Protection is provided by a limited 3-year warranty..