The RX1222sas is a plug-and-play capacity expansion unit for Synology servers. Expand your Synology rackmount SAS storage 12 bays at a time, for up to 84 additional 8.9 cm (3.5") / 6.4 cm (2.5") SAS/SATA drives with a maximum of seven Synology RX1222sas expansion units. Add volumes when and where needed without interrupting services, thanks to Synology DiskStation Manager (DSM)'s online volume expansion and powerful volume management options.