The Synology RX418 is a compact 4-bay 1U rackmount expansion unit designed to provide seamless storage expansion for compatible Synology RackStation NAS servers, including RS818+, RS818RP+, RS815+, RS815RP+, RS816, RS815, RS1221+, RS1221RP+, RS822+, and RS822RP+ models. Featuring four hot-swappable drive bays that support both 3.5" and 2.5" SATA HDDs and SSDs, the RX418 offers plug-and-play capacity expansion through a single eSATA connection. The expansion unit operates as an extension of the host RackStation, with drives managed directly through Synology's intuitive DiskStation Manager (DSM) without requiring additional software installation. With its space-efficient 12-inch depth design, the RX418 fits easily in 2-post racks and wall-mount racks, making it ideal for space-constrained deployments. The unit can also function as a dedicated local backup destination for comprehensive data protection. Supporting online volume expansion and featuring energy-saving deep sleep mode with configurable drive hibernation, the RX418 provides reliable storage scalability for growing business data needs in branch offices and SMB environments, backed by a 3-year hardware warranty (extendable to 5 years).