The RX418 is a 4-bay rack expansion unit that adds storage to a Synology RS818+, RS818RP+, RS815+, RS815RP+, RS816 or RS815, or serves as a dedicated local backup target for Synology 1U RackStations. Its four hot-swappable bays natively support 3.5" and 2.5" SATA hard drives and SSDs, connecting to the host via an eSATA port. RAID is managed through the host's Synology DiskStation Manager, and a 100W power supply runs the unit.