The Synology RX1217RP 12 Bay Diskless Expansion is a black 3.5-inch expansion unit designed for the Synology RS3617xs NAS server. It offers 12 bays for HDD and SSD drives, with a storage capacity that is unpopulated. With a transfer rate of 6 Gbit/s and SATA III interface, this expansion unit is ideal for expanding the storage capabilities of the NAS server. The Synology RX1217RP is a reliable and high-performance solution for businesses and individuals looking to enhance their storage capacity.