This Synology unit is a 24-bay 2.5-inch expansion chassis built to extend the storage capacity of a compatible Synology FlashStation host system — it connects to the host over a dedicated expansion port/cable rather than acting as a standalone network storage device, adding another 24 SSD bays' worth of raw flash storage capacity once the host's own bays are full. Expansion units like this let IT departments grow an existing all-flash storage deployment for virtualisation, databases or other high-IOPS workloads without replacing or migrating off the original FlashStation, making it a scale-up purchase for organisations that have already outgrown their host unit's internal bay count.