Featuring dual controllers, an OLED indicator, and a short-depth rackmount design, the 3U 16-bay TL-R1620Sdc SAS 12Gb/s storage expansion enclosure is ideal for expanding the storage capacity of dual-controller QNAP NAS. Both controllers have three Mini-SAS HD (SFF-8644) ports, supporting 12Gbps SAS and Broadcom SAS DataBolt bandwidth optimization technology. The dual path mini-SAS design sustains continuous operations even if an external JBOD cable is disconnected. Up to 7 TL-R1620Sdc units can be daisy-chained via high-speed Mini-SAS HD cables, providing scalability and high reliability for mission-critical storage of file servers, virtualization, surveillance, medium-sized data center, multimedia, and more.