This product is either discontinued or we cannot get that from suppliers.
Synology RackStation RS819 4-Bay Scalable Diskless NAS, Quad-Core 1.4GHz CPU, 2GB DDR4 , Bays 4, 3.5" SATA HDD, 2.5" SATA HDD/SSD, 56TB (14TB x 4), 108TB, Hot Swappable Drive, 2x RJ-45 1GbE LAN, 2x USB 3.0, 1x eSATA.
The RackStation RS819 4-Bay NAS Enclosure from Synology brings business workgroups simple, comprehensive solutions to data management, sharing, synchronization, and backup.